Make: Electronics

Errata for Make: Electronics

Submit your own errata for this product.


The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color Key: Serious Technical Mistake Minor Technical Mistake Language or formatting error Typo Question Note Update



Version Location Description Submitted By Date Submitted Date Corrected
Printed, PDF
Page xi
paragraph 4

Page xi, paragraph 4 please change: Some Shacks have more components than others, but almost all of them have the basics that you'll need. To: Some Shacks have more components than others. Many may carry the Maker Shed kits that were developed to go with this book.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed, PDF
Page xi
under "Fundamentals"

Page xi, under "Fundamentals", please change: Here are the primary mail-order sources that I use myself online: http://www.radioshack.com RadioShack, a.k.a. The Shack. For tools and components. Not always the cheapest, but the site is easy and convenient, and some of the tools are exactly what you need. to this: Here are the primary mail-order sources that I use myself online. I leave it to you to shop around for bargains, if you are so inclined. http://www.radioshack.com RadioShack, a.k.a. The Shack. For tools and components. The site is easy and convenient, and some of the tools are exactly what you need.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed, PDF
Page 1
under "Small pliers"

On page 1, under "Small pliers", the "RadioShack Kronus 4.5-inch, Part number 64-2953" should read "RadioShack 4.5-inch Mini Long Nose Pliers, Part number 64-0062"

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed, PDF
Page 2
under "Wire cutters"

On page 2, under "Wire cutters", the "RadioShack Kronus 4.5-inch, Part number 64-2951" should read "RadioShack 4.5-inch Mini Diagonal Cutters, Part number 64-0061"

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed
Page 3
Last paragraph of page, under "Battery holders and connectors"

Mouser.com catalog number 12BH410-GR is for a battery holder for a single AAA cell. The Mouser.com catalog number for a battery holder for a single AA cell (by the same manufacturer, also 6" leads-tinned 3/16") is 12BH311A-GR.

Note from the Author or Editor:
The correction is valid.

M. L. Liu  Feb 17, 2010  Dec 01, 2010
Printed
Page 6
First paragraph in the yellow box titled "Ohms"

The first sentence of the paragraph reads: "We measure distance in miles or kilometers, weight in pounds or kilograms, temperature in Fahrenheit or Centigrade—and electrical resistance in ohms." For your information, weight is a force measured in pounds-force or Newtons, not pounds-mass or kilograms.

Note from the Author or Editor:
Page 6, first para under "Fundamentals" heading, delete "weight in pounds or kilograms," and substitute "mass in pounds or kilograms,"

Repentinus  Nov 24, 2013  Feb 07, 2014
Printed
Page 7
The green-dotted box

The boxed paragraph states: "When your skin is moist (for instance, if you perspire), its electrical resistance decreases. This principle is used in lie detectors, because someone who knowingly tells a lie, under conditions of stress, tends to perspire." Polygraphs, more colloquially known as lie detectors, are pieces of pseudoscientific junk. While it is true that moistening skin tends to increase its conductivity due to creating an electrolytic solution on the skin, and it is also true that polygraphs measure such changes, the conjecture that someone who knowingly tells a lie tends to perspire (more than usual) remains unproven and polygraphing is regarded as junk science.

Note from the Author or Editor:
Page 7, boxed paragraph. Delete the last three words, "tends to perspire." and substitute "may tend to perspire."

Repentinus  Nov 24, 2013  Feb 07, 2014
PDF
Page 8
BACKGROUND

resistance ... is *inversely* proportional to its area of cross section

Note from the Author or Editor:
Oops! An embarrassing error. Amazing that no one saw it before. The one-word correction suggested by the reader should be implemented.

lafros  Sep 04, 2010  Dec 01, 2010
Printed
Page 9
Experiment 2

It should state you need Alligator clips to perform the experiment.

Note from the Author or Editor:
The "You will need:" list on page 9 should be expanded to mention one alligator clip.

Glen73  Feb 04, 2010  Mar 01, 2010
Printed, Safari Books Online
Page 10
"Background" inset

Under "Here are some other basic concepts" bullet item "The pressure of electricity causes the flow, measured in volts." the language seems ambiguous. To me the sentence reads pressure causes flow and flow is measured in volts which in fact it is not.

Note from the Author or Editor:
Good point. The phrase should be rewritten: The pressure of electricity, measured in volts, causes the flow.

Anonymous  Dec 14, 2010  Feb 01, 2011
Printed
Page 12
2nd paragraph in Fundamentals section

Is it just me or is the info about the frequency of changes from positive to negative from the 'hot' wire in a power outlet in your home mixed up? I live in North America and I'm pretty sure ac changes from + to - 60 times a second (60hz) and in Great Britain (UK) it changes at 50Hz. Just thought I would put it out there. Great book! ~d

Note from the Author or Editor:
The frequency of alternating current in the United States vs. Europe was stated incorrectly on page 12. The sentence should read, "It changes from positive to negative 60 times each second (in Great Britain and some other nations, 50 times per second)." In the printed version, the numbers 50 and 60 are reversed.

Darsha Hewitt  Jan 19, 2010  Mar 01, 2010
Printed
Page 19
Figure 1-50 caption

The LED burns out because turning down the resistance allows more current (amps) to flow given the same voltage. The explanation states that the potentiometer is protecting the LED from voltage. That's not right. The potentiometer (which is actually only being used as a rheostat, since only 2 leads are connected) is limiting the amount of current (amps) that will flow through the circuit if it is connected to a 6 volt power supply. Resistance is measured as amps per volt; one ohm of resistance means one amp per volt of potential. Since the potential is supplied by the battery here and we are not changing it, varying the resistance causes a change in the current (amps) flowing through the circuit. If we connected the 3rd lead on the potentiometer and used it as a voltage divider, then we could vary the voltage by splitting part of it off to a ground.

Note from the Author or Editor:
I believe you are referring to the caption on Figure 1-50. While it is true that the LED burns out because the potentiometer allows more current to flow through it, it is also true that the potentiometer allows a higher voltage *measured across the LED.* Just because the potentiometer causes a change in current, does not mean it cannot cause in a change of voltage at the same time, across a component connected in series with it. Note that any datasheet will specify a maximum forward voltage for an LED. So, I would say that the caption is correct, but mentioning amperage would certainly improve it.

None  Dec 16, 2011  Oct 12, 2012
Printed
Page 22
3rd (last) paragraph

I believe the figure reference is incorrect in the sentence: "As you turn the potentiometer up and down, you should get exactly the same results as with the configuration in Figure 1-64." should be: "As you turn the potentiometer up and down, you should get exactly the same results as with the configuration in Figure 1-62." Even though the statement is true, you don't really introduce Figure 1-64 until the top of page 23. Thanks. PS: I'm really enjoying the book.

Note from the Author or Editor:
The reader's suggestion is correct.

Rich Burridge  Apr 11, 2010  Feb 01, 2011
PDF
Page 28
Just after "How Big a Resistor Does an LED Need?" section heading

"Suppose that we're use the Vishay LED. Remember its requirements from" ... Is incorrect English. The best correction that I can guess is Suppose that WE use the Vishay LED. Remember its requirements from

David Ciochetto  Mar 26, 2010  Dec 01, 2010
PDF
Page 29
Fundamentals box

At the "Make: Electronics Book", specially at the sample PDF: http://cdn.makezine.com/make/shed/make_electronics_1.pdf Page 29, it explains how to multiply numbers. Unfortunately, the explanation is wrong. It says to count the number of zeros, write all zeros and then write the multiplication result, like this: 0.04 * 0.005 = 0.00020 However, this is NOT true for every multiplication. Following the book advice, I would conclude that: 0.04 * 0.002 = 0.0008 Which is WRONG. The correct result is 0.00008

Note from the Author or Editor:
The complaint is correct. The text should be modified to state that the count-the-zeroes rule only works if the two numbers being multipled create a product that creates a "carry one."

Anonymous  Jan 29, 2010  Mar 01, 2010
Printed
Page 31
2nd paragraph in the yellow box

Contrary to what the book claims, watt is not a unit of work, but a unit of power. FYI, joule is a unit of work.

Note from the Author or Editor:
Page 31 in the "Fundamentals" section, second line. Delete "A watt is a unit of work." Substitute "A watt is a unit of power, and when power is applied over a period of time, it performs work." In the third para, delete "which can be measured in watts. The definition is easy:" and substitute "which can be measured in watts per second. The definition of a watt is easy:"

Repentinus  Nov 24, 2013  Feb 07, 2014
Printed
Page 31
Theory

s/b "I mentioned earlier 'that' resistors are commonly...."

Glen  Feb 11, 2010  Dec 01, 2010
Printed
Page 33
First paragraph under Figure 1-73, second line.

The sentence reads "when a wire connects the zinc electrode, which has a surplus of ELECTRONICS, ..." should read: "when a wire connects the zinc electrode, which has a surplus of ELECTRONS, ..."

Note from the Author or Editor:
This complaint is correct, and the word should be changed in any future edition.

Mike Parks  Jan 20, 2010  Mar 01, 2010
Printed
Page 33
First column, last line

From First Edition, December 2009: Last line on page reads: "... replacing the missing electrodes with new ones ..." Should read: "... replacing the missing electrons with new ones ..." (This is similar to, but different from, the error Parks reported.)

Note from the Author or Editor:
The text should be changed as the reader suggests.

Scott White  Jul 05, 2010  Feb 01, 2011
Printed, PDF
Page 39
under "Devices"

On page 39 under "Devices" -> "Power supply/universal AC adapter, 3-12 volts at 1A (1,000mA)," "Part number 273-029 from RadioShack" should read "Part number 273-0316 from RadioShack"

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed
Page 39
First bullet under "devices"

The RadioShack part number (273-029) for the 3-12v universal AC adapter is incorrect, it should be listed as 273-316. Additionally, for figure 2-1 on the same page, the image is incorrect and does not match the caption (which is correct).

Note from the Author or Editor:
Radio Shack changed the part number. This was reported previously and should be correct in current editions. Because reshooting the photograph would be inconvenient at this point, the caption to Figure 2-1 should be revised to read: AC adapters of this general type can supply a variety of voltages, with a range as wide as 3 to 12 volts.

Anonymous  Jan 04, 2011  Feb 01, 2011
Printed, PDF
Page 40
under "Wire Strippers"

On page 40 under "Wire Strippers"->"Kronus Automatic Wire Strippers", "part number 64-2981 from RadioShack" should read "part number 64-0083 from RadioShack"

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed
Page 41
1st paragraph

[CORRECTION to previous submission by same submitter! Ignore previous submission please.] On page 41, under Supplies / Hookup wire it is suggested to buy 22 AWG wire, and the Radio Shack part # given is: 278-1222 i.e. http://www.radioshack.com/product/index.jsp?productId=2049743 75-Ft. UL-Recognized Hookup Wire (20AWG) Model: 278-1222 | Catalog #: 278-1222 which is 20 AWG. So I think that ought to be instead ---> http://www.radioshack.com/product/index.jsp?productId=2049742 90-Ft. UL-Recognized Hookup Wire (22AWG) Model: 278-1221 | Catalog #: 278-1221

Note from the Author or Editor:
The error exists as stated, although it will not affect the functionality of the experiment. Thanks for pointing it out.

Richard Phillips  Feb 14, 2010  Dec 01, 2010
Printed
Page 42
2nd paragraph under "Transistors"

In the shopping list for experiments 6 through 11 you specify on page 42 a Quantity of 4 for 2N6027 programmable unijunction transistors. The 2N6027s are used only in experiment 11 and only two are needed. I suggest you change the "Quantity: 4" on page 42 to "Quantity: 2". Great Book. I hope you are working on Book 2.

Note from the Author or Editor:
I was allowing for the possibility of people destroying transistors accidentally. The text should be modified: Quantity: 4 (allowing for 2 spares in case of damage)

Bruce Robitaille  Feb 17, 2011  Apr 29, 2011
Printed
Page 42
Relays

This comment is more of a clarification. The relays you refer to in the book (part numbers) are different from the relays that came in my components pack 1. The relays that came in the components pack 1 I bought at the SF Maker Faire was a HLS-4078-DC12V. The arms/poles are attached to different pins. I initially assumed that the relays that got incorporated in the components pack 1 would match with the book. It took me a while to figure this out when I was having trouble getting exercises 7 and 15 to work. You might want to consider alerting readers to this fact or even contacting MakerShed so that they can source the correct relays. Sincerely, Stephen Fisher

Note from the Author or Editor:
The relays supplied in the component pack were incorrect, as the writer states. I have communicated with MakerShed and I have been told that the problem has been resolved.

Stephen Fisher  Jul 01, 2011 
Printed
Page 42
1st paragraph under 'Capacitors'

In the shopping list for experiments 6 - 11, you specify on page 42, first paragraph under 'Capacitors', "Electrolytic capacitors, assorted. Must be rated for a minimum of 25 volts and include at least one capacitor of 1,000 microfarands." However, in experiment 11 (the only experiment in this series to use a capacitor other than the 1,000 microfarand capacitor) you use the 1,000 microfarand capacitor and two 2.2 microfarand capacitors. My suggestion is change the wording to say: "Electrolytic capacitors, assorted. Must be rated for a minimum of 25 volts and include at least one capacitor of 1,000 microfarands and two capacitors of 2.2 microfarands." This will help reduce the number of shopping trips! Great book BTW. My 12 year old son and I are thoroughly enjoying it.

Note from the Author or Editor:
The complaint is correct: The shopping list on page 42 should be modified as suggested.

Anonymous  Jan 04, 2011  Feb 01, 2011
Printed
Page 43-44; 50
43: second-to-last paragraph; diagrams 2-17, 2-18, 2-22, 2-35

Several other readers have pointed out this Experiment 6 LED-and-leads orientation issue already, and the author responded that it had been corrected, but I was unclear on the nature of the correction after reading the other errata. Without rehashing the problem reported by Ciochetto, Bogart and Parsons, I believe these are the specific corrections that need to be made. (My copy of the book says 'December 2009: First Edition) * Figure 2-17 should be revised to indicate the red lead connecting to the resistor, the blue lead connecting to the switch, and the orientation of the LED reversed (long lead connecting to the resistor, short lead to the switch). * Photos 2-18 and 2-22 should be revised to show the red lead connecting to the resistor and the black wire connecting to the switch. * The text on page 45 saying that the long lead on the LED should connect to the resistor and the positive side of the circuit is correct and should remain as-is. * Schematic 2-35 on page 50, which shows the positive lead connecting to the resistor and then the LED is correct and should remain as-is.

Note from the Author or Editor:
The reader's summary is very helpful and is correct. NOTE: Figure 2-17 has been fixed in both the printed and digital products for the 2/11 printing. Figure 2-18 and 2-22 need to be reshot (new photographs).

Scott White  Jul 05, 2010  Oct 12, 2012
PDF
Page 43 - 44
Next to last paragraph

The next to last paragraph on page 43 does not match Figure 2-17 on page 44. The text correctly states that the LED's long lead must be connected to the more positive side of the circuit. However regarding Fig 2-17, the convention established earlier in the book is that red is more positive than blue leaving the battery packs. This does not go to the resistor. Also the long lead in Fig 2-17 is correctly labeled as going to the red lead. The text needs to be adjusted to indicate this correctly.

Note from the Author or Editor:
This was reported previously, and Figure 2-17 was modified in the second printing of the book.

David Ciochetto  Mar 30, 2010  Mar 01, 2010
Printed
Page 43
Top of page, 2nd paragraph of "Capacitors"

In regard to the following sentence, is the conversion correct?: "Make sure you get at least one rated at 0.0047 uF (which can also be written as 47nF)." Is 0.0047 uF equal to 4.7 nF, not 47 nF?

Note from the Author or Editor:
The correction is valid.

M. L. Liu  Feb 17, 2010  Dec 01, 2010
Printed
Page 44
Figure 2-18 (and figure 2-22 on page 45)

Both photographs of the circuit being discussed have the black and red leads from the battery swapped from the diagram in Figure 2-17. This matters because the text makes a point about which way to hook up the LED in the circuit.

Note from the Author or Editor:
This complaint is valid. The two photographs show the colored wires from the battery with polarity opposite to the diagram in Figure 2-17. The diagram should be revised to match the photographs. I apologize for this error.

Chris Bogart  Jan 23, 2010  Mar 01, 2010
Printed
Page 44,45
figure 2-18, figure 2-22

If you go back to the shopping list on page 4 figure 1-10 you see a pic of 4AA battery pack(6 volt). Page 17 figure 1-44 and page 19 figure 1-51 also shows this battery pack. When you reach pages 44 and 45 it shows what looks to be a 2AA pack. Either it is the wrong battery pack or perhaps a different style that has the other 2 on the bottom? Still it may throw a curve ball at some beginners. good book!

Note from the Author or Editor:
This complaint is correct but the fix will entail adding one 2-battery carrier to the shopping list on page 4, and revising the list of parts needed on page 43, which should be changed to specify 2 AA batteries, and a battery carrier for 2 AA batteries, instead of 4 AA batteries and a carrier for 4 batteries.

Anonymous  Jan 31, 2010  Mar 01, 2010
Printed
Page 44
2-17

would it be possible to have a clear and correct schematic for figure2.17 and 2.48 which seems both being wrong. This is confusing as different people have different version of the book. Thanks a lot, Laurent

Note from the Author or Editor:
The circuit will work as shown but in Figure 2-17 the red wire should be blue and the blue wire should be red. This error has previously been reported and a corrected diagram was submitted to the publisher.

Laurent  Jan 06, 2011  Dec 01, 2010
Printed
Page 44
Fig. 2-17

The Battery Pack in Figure 2-17 should correctly be labeled "3v Battery Pack"

Note from the Author or Editor:
The error report is correct. I'm not sure if this error has been fixed in figure 2-17 of the current edition of the book. If not, it should be fixed as suggested.

MK Grady  Oct 06, 2010  Feb 01, 2011
Printed
Page 50
United States

NOTE: I don't have the book with me, but it's around page 50, experiment 8. Please correct the page number for me. You can remove this NOTE from my submission. The text says "Now, when you press the button, the contacts in their relaxed state feed power to the coil as well as to the lefthand LED." But is "lefthand" referring to the lefthand LED in figure 2-63 or the schematic? I scratched my head for a long, long time thinking it was referring to figure 2-63, which didn't make sense. Later on in the same paragraph: "This interrupts the power to the coil and the contacts close again", etc. That sounds confusing to me as well. Which of the two contacts are closed again? Maybe it would be better to reword the whole paragraph by labeling each PAIR of the contacts and refer to them in the text. "We start with C1 closed, which energizes the coil and throws the moving arm of the relay up making C2 closed, but since nothing forces the moving arm to remain in that position, it (the arm), because of its own tension, bends back, which again makes C1 closed and energizes the relay -- the process continues indefinitely." Something along those lines would eliminate the problem for me at least.

Note from the Author or Editor:
Page 60 of book, first edition. This page has the subhead "Experiment 8: A Relay Oscillator" at the top of the page. The reader states that the positions of LEDs in diagrams 2-59, 2-63, and 2-65 are opposite to the positions of LEDs in schematics 2-60, 2-64, and 2-66. However, this difference may only apply to some relays. At one point, MakerShed was distributing relays with opposite pin configuration, and I don't know if this reader got one of them. So, the easiest way to fix this is to change the first sentence of the third paragraph from the bottom of the page. Current text: "Now, when you press the button, the contacts in their relaxed state feed power to the coil as well as to the lefthand LED." Please substitute this text: "Now, when you press the button, the contacts in their relaxed state feed power to the coil as well as to the lefthand LED, as shown in the schematic."

Sergei  Oct 18, 2012  Dec 14, 2012
Printed
Page 50
Figure 2-35

Positive and Negative terminals are reversed from the book text. See the errata for page 44 (Figure 2-17) for more details.

Note from the Author or Editor:
As I recall, this error was previously reported and the diagram was revised for the second printing.

Richard Parsons  Mar 21, 2010  Mar 01, 2010
PDF
Page 54
figure 2-47

The text above and below Figure 2-47 state that it represents Experiment 4 show in Figure 1-50, page 19. However in figure 1-50 the LED is connected to the wiper on the potentiometer, and in Figure 2-47 (the schematic) the negative terminal is connected to the wiper. Am i seeing this correctly? If so, one is a mistake i believe.

Note from the Author or Editor:
The reader is correct, and Figure 2-47 should really be redrawn.

nate stephens  Dec 25, 2012  Jul 19, 2013
Printed
Page 54
2nd paragraph

The Book States: "Compare the example in Figure 2-48, showing the two DPDT switches, with the version shown back in Figure 2-35." It should say: "Compare the example in Figure 2-48, showing the two SPDT switches, with the version shown back in Figure 2-35."

Note from the Author or Editor:
The reader has described the error and the necessary correction correctly.

Anonymous  Apr 26, 2013  May 10, 2013
Printed, PDF, Safari Books Online, Other Digital Version
Page 55
Right hand column

Some readers have written in with questions about measuring voltage from an AC adapter. The author suggests the following change, which could be represented as a "Fundamentals" box/sidebar in a future printing, if there is room for it: Measuring Voltage from an AC Adapter If you plug your AC adapter into a power outlet and then attach a meter across its output (with the meter set to measure DC volts), you may get a confusingly high reading. This is because the voltage delivered by some AC adapters will be significantly greater when the adapter is not heavily loaded, and the internal resistance of your meter is so high, the adapter will behave as if it isn't being loaded at all. For a more meaningful test, select a resistor with value 680 ohms and put it across the output from the adapter. This will pull the voltage from the adapter down to a more appropriate level. Apply your meter in parallel with the resistor. It's not a good idea to use a resistor of less than 680 ohms because the resistors on your shopping list are only rated at 1/4 watt, and if you try to push more power through them than that, they will overheat and burn out. When the 680-ohm resistor is attached to a 12-volt supply, Ohm's Law tells us that the current flowing through it will be about 17.7 mA, and therefore the power dissipation will be about 0.21 watts. However, you can put several resistors in parallel across the output from your AC adapter if you want to see how its voltage output varies with a heavier load.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Jan 26, 2011  Nov 11, 2011
Printed
Page 55
3rd paragraph, first line

Line begins: Similarly, when you raise the lid on an a top-loading (Should drop the "an")

Note from the Author or Editor:
The reader has described the error and the necessary correction correctly.

Michael Sklar  Mar 25, 2013  May 10, 2013
Printed
Page 59
sidebar, bottom of page

There is a reference to this website for larger versions of schematics. There is no link on the website to get this information.

Note from the Author or Editor:
All of the schematics, and larger versions of some of the photographs, are now available from the O'Reilly website via the "Download Example Code" link. You can also download them from this source: http://cdn.makezine.com/make/books/MakeElectronics_figs.zip

Brian Lutton  Dec 28, 2009  Oct 12, 2012
PDF
Page 61
4th paragraph

The capacitor charges before the relay has time to open. The later discussion of the time constant suggests that a resistor in series with the capacitor would prevent the capacitor from fully charging and hence would reduce the cycle time in the circuit in Figure 2-66. This is what happens when I insert a resistor. Perhaps it would make sense to discuss Figure 2-66 again when talking about the time constant --- it would have solidified my understanding of figure 2-66.

Note from the Author or Editor:
This is a good suggestion but would require a rewrite and new schematic, which may not be practical at this time. Since the circuit does work as shown, I am reluctant to make modifications.

None  Jul 26, 2011 
Printed
Page 62
last paragraph

Refer back to figures 2-14 and 2-15, not 2-13 and 2-14

Glen  Feb 11, 2010  Dec 01, 2010
Printed
Page 71
3rd paragraph

Trivial typo (stray period): Where TC is the time constant, in seconds, and a capacitor. [REMOVE PERIOD]

Note from the Author or Editor:
On page 72, in the line of text immediately below the first formula on this page, the text contains the words capacitor. of The period should be removed, so that the text looks like this: capacitor of

Michael Sklar  May 11, 2013  Oct 18, 2013
Printed
Page 71
First sentence of 3rd para in 1st column

I suggest you change "where TC is the time constant, and a capacitor..." to "where TC is the time constant, in seconds, and a capacitor...". At present, the first reference to the time unit is in the first sentence of the second column of this page, and there it is oblique.

Note from the Author or Editor:
I agree with the suggested change.

Cary Swoveland  Oct 02, 2010  Feb 01, 2011
Printed
Page 73
Figure 2-84

In figure 2-84 the picture shows the 2N2222 transistor with flat side to the right and collector on top, base in the middle and emitter on the bottom. I purchased the parts kits from Radio Shack that go with the book and the part included for the exercise shown in figure 2-85 is P2N2222A. Exercise did not work properly. LED lit up slightly dim then went brighter upon pressing the button. I finally figured out the issue by looking up the data sheet for the transistor on Mouser.com. The included part has the Collector and Emitter switched around from the type shown in the book. It is listed as an obsolete part. If others are having the same issue they have to turn the transistor with the flat side to the left and it will work properly.

Note from the Author or Editor:
Radio Shack parts kit is shipping with the wrong type of transistor: P2N2222A instead of 2N2222. This needs to be fixed ASAP. It is not a problem with the book.

JWulf  Dec 29, 2013 
Printed, PDF
Page 73
Figure 2-85

Some versions of the companion kit from RadioShack (Component Pack 1) may include a P2N2222 rather than the 2N2222. The 2N2222 or PN2222 or PN2222A will have its flat side on the right, but if you happen to have the P2N2222 or P2N2222A or any other transistor whose part begins with P2N2222, you must reverse it so that the flat side is on the left (viewed from above). This affects Experiment 10 as well as any other experiment that calls for the 2N2222.

Note from the Author or Editor:
Add this important text as an additional paragraph to the caption for Figure 2-84. There is sufficient white space to allow this: Beware of confusion using part numbers P2N2222 and P2N2222A. Some were made by On Semiconductor and may be supplied by Radio Shack. Their pins are reversed, so that the part should be used with its flat side on the left, not on the right as in the diagram above. The diagram above is correct for parts such as 2N2222, PN2222, or PN2222A, but not for parts with numbers begining P2N.

Brian Jepson  Dec 30, 2013  Feb 07, 2014
Printed
Page 73
List of items needed for the experiment

Add 1megaohm potentiometer to the list (assuming it is not subsumed under the reference to resistors).

Note from the Author or Editor:
On Page 73, in the list headed "You will need:" we should add: Potentiometer, 1 megohm, linear.

Cary Swoveland  Oct 02, 2010  Feb 01, 2011
PDF
Page 74
Second paragraph

Text says that when voltage is applied to the base of the transistor it "opens" its switch and allows current to flow through the emmiter. A switch has to CLOSE to allow current to flow through it.

Note from the Author or Editor:
Funny no one else noticed this error.

Anonymous  Jun 08, 2011  Jul 15, 2011
PDF
Page 78
1st paragraph

These comments are based on this statement in "MAKE:Electronics": "There's no dispute that the first working transistor was developed at Bell Laboratories in 1948 by John Bardeen, William Shockley, and Walter Brattain." I'm not a historian or electronics expert but, based on what I've read elsewhere, I believe the above statement is incorrect. The following information is documented in various places on the internet. I provide links for most of it. Apologies for any typos or inaccuracies. IEEE.org states: "The underlying concept of the MOSFET-modulation of conductivity in a semiconductor triode structure by a transverse electric field-first appeared in a 1928 patent application." http://goo.gl/ro3Up That first transistor was invented around 1923, by physicist Dr. J. Edgar Lilienfeld: a silicon metal-oxide-semiconductor field-effect modulation of conductivity in a semiconductor triode structure by a transverse electric field (a MOSFET transistor). This is not the diode Mr. Platt mentions. While the devices did not perform to today's standards, signal amplification was detected. The exact construction employed and performance obtained by Lilienfeld remain unknown. Lilienfeld's patent numbers are: # 1,745,175 Method and Apparatus for Controlling Electric Currents # 1,877,140 Amplifier for Electric Current # 1,900,018 Device for Controlling Electric Current Because of Lilienfeld's prior art, the Bell Lab's field effect transistor patent, and half the claims in its point junction transistor patent application, were disallowed by the US Patent Office. "Undisputed" indeed. Bell Labs had built working devices described by Lilienfeld's patents, but made no mention of Lilienfeld in any Bell research papers, nor in the Bell Labs version of transistor history. Robert G. Arns, Professor of Physics at the University of Vermont, discovered a 1948 patent deposition by John B. Johnson (of Johnson noise fame) stating that Bell Labs had built an aluminum oxide MOSFET called out in Lilienfeld's patent, found useful power amplification, and published the result without reference to Lilienfeld. In this sworn testimony to the U.S. patent office in 1949, Johnson reported "...although the modulation index of 11 per cent is not great,...the useful output power is substantial...it is in principle operative as an amplifier". Johnson was possibly among the first people to make a working field effect transistor, based on Julius Edgar Lilienfeld's US Patent 1,900,018 of 1928. Mr. Johnson later denied this, and contradicted himself: in an article in 1964 he denied the operability of Lilienfeld's patent, saying "I tried conscientiously to reproduce Lilienfeld�s structure according to his specification and could observe no amplification or even modulation." This contradiction, plus the rejection of Bell Lab's patent applications referred to above, seems to refute Mr. Platt's use of the word "undisputed". It's also a rich drama that would make for a great read. I'm not saying Mr. Platt should recount all the details, but a summary appropriate to his book. If he chooses to address it, it remains to be seen whether his summary gives a true picture of the history and dispute, or whether it's a whitewash. http://amasci.com/amateur/transis.html#lilienfeld http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05217015 http://tikalon.com/blog/blog_archive/2008/January.html#who_invented_the_transistor http://en.wikipedia.org/wiki/John_B._Johnson#Field-effect_transistor ========= There's more. "This business of the French transistors would be hard to unravel, i.e., whether [Welker and Matar�] developed [the transistor] independently," [Bell Labs researcher Alan Holden] confided in a 14 May letter to William B. Shockley. "As we arrived [at the Paris lab, the German team was] transmitting to a little portable radio receiver outdoors from a transmitter indoors, which they said was modulated by a transistor." Four days later, France's Secretary of Postes, T�l�graphes et T�l�phones (PTT) announced the invention of the transistron to the French press. In early 1945, [German researcher] Welker recognized that the two semiconductors could be used to make what we now call a field-effect transistor. In fact, the device he had in mind was strikingly similar to one that Shockley was to suggest at Bell Labs a few months later. ... Given the secrecy shrouding the Bell Labs device, there is no possibility Matar� and Welker could have been influenced by knowledge of it before July 1948, when news of the revolutionary invention became widespread. But it seems from the still-sketchy historical record that they may well indeed have had a working amplifier before Bell Labs. ======== No dispute, indeed. Ironically, it was finally the needs of computers and the opportunities created by integrated circuits that made Lilienfeld's 1928 silicon MOSFET technique the basic element of late 20th-century digital electronics, and NOT the Shockley transistor. ========== From Radio Bygones magazine: www.radiobygones.com Radio historian Lawrence A. Pizzella WR6K notes anecdotal stories of shipboard wireless operators in the second decade of the 20th century achieving amplification using a silicon carbide (carborundum) crystal and two cat�s whiskers. He cites an interview with Russell Ohl, who's accidental discovery of the P-N barrier in his work at Bell Telephone Laboratories led to the development of solar cells. Pizzella says Russell Ohl showed William Shockley his radio using crystal amplifiers several years before the transistor�s alleged invention in 1947. Shockley is also quoted (in Crystal Fire by Riordan and Hoddeson) as saying that seeing Ohl�s radio convinced him that an amplifying crystal could be made. A fascinating letter to Wireless World in May 1981 under this title came from Dr Harry E. Stockman. Says Stockman, himself a distinguished author of many books and papers on semiconductor physics, �Lilienfeld created his non-tube device around 1923, with one foot in Canada and the other in the USA, and the date of his Canadian patent application was October 1925. Later American patents followed, which should have been well known to the Bell Labs patent office. Lilienfeld demonstrated his remarkable tubeless radio receiver on many occasions, but God help a fellow who at that time threatened the reign of the tube.� It seem VERY disputed that Bell Labs invented the transistor. The fact that they intentionally failed to acknowledged the pioneering work done by others can be explained by capitalist motivations, and by human nature�pride, arrogance, and plain self-interest. It may be true that the world wasn't ready for previous incarnations of the transistor, but that was no reason for denying that Lilienfeld patented the original solid-state triode oscillator/amplifier well before others claimed all the credit. http://www.porticus.org/bell/belllabs_transistor1.html =============== It may be that the Bell Labs transistor represented new innovations. But, whether the above history is true or not, it is not correct for Mr. Platt to say Bell Labs claims are "undisputed"-- and unfair to say nothing about the above history. If Mr. Platt wrote that the Bell Labs device was the first of that TYPE of transistor, that might be better, but he does not say that. If the alternative history above is true, then this reminds me all too much of the way Thomas Edison and others are routinely given credit for some of Nikola Tesla's inventions. I'll optimistically assume Mr. Platt was simply was unaware of this rarely talked-about history, or felt the evidence was too weak-- and not that he or O'Reilly is on Bell Lab's payroll, or that Mr. Platt hates to credit Jews or Germans with anything. This human drama of technological history would make a fascinating, and i think, more honest addition to the book. PS, I'll be sharing these thoughts with my colleagues in the Bay Area maker community-- perhaps someone will convince me Mr. Platt's description is correct.

Note from the Author or Editor:
A rewrite is needed of this section.

Johny Radio  Jan 08, 2013  Oct 31, 2014
Printed
Page 80
Second column, third paragraph

The text reads "The current emerging from the emitter of the transistor, through location A2, is about 24 times the current passing through location A1, into the base." - the table in the same column on the same page suggests a factor of 240, though.

Note from the Author or Editor:
The reader is correct, and the statement in the text should be modified accordingly. Thanks for pointing it out.

Anonymous  Mar 13, 2010  Dec 01, 2010
Printed
Page 83
Last sentence of 5th paragraph

The sentence should state "The voltage at the GATE determines when the PUT allows current to flow". Typically once the anode voltage is about 0.7V greater than the gate voltage, current will flow from anode to cathode. Thus it is the GATE voltage that "programs" a PUT.

Note from the Author or Editor:
In fact when the voltage on the anode crosses a threshold, it does force the PUT to pass current from anode to cathode. But the voltage on the gate programs where the threshold will be. This is why the component is said to be "programmable." I will add a sentence on page 83 to make this clear.

Michael Parks  Sep 02, 2012  Oct 12, 2012
Printed
Page 83
6th Paragraph

This may just be my misinterpretation. However, the sentence "The transistor blocks it until the anode gets close to 6 volts." coupled with the discussion on page 85 about the capacitor needing 5 seconds to charge to 6 volts lead me to expect the LED to flash once every 5 seconds.Granted there was verbiage about a "threshold", but it was unspecified and I assumed that it was close to 6 volts as well. After some poking around with data sheets and a multimeter, it looks like the gate voltage is around 3.8 V with the circuit as depicted in figure 2-103 and the offset voltage is roughly .4 V, so the 6027 triggers around 4.2 V which happens very roughly at 2 Hz (rather than the .2 Hz that I was originally expecting). Summing up, I guess I don't consider 4.2 volts to be "close" to 6 volts. Again, I hesitate to call this an error but I didn't see a "comment" option. Feel free to put this in a more appropriate category.

Note from the Author or Editor:
The reader is correct. On page 83 there is this sentence: The transistor blocks it until the anode gets close to 6 volts. Please change this sentence so that it reads: The transistor blocks it until the anode is above 4 volts.

John Robinette  Sep 09, 2013  Oct 18, 2013
Printed
Page 85
Theory Box

This was corrected from previous input is seems like but the correction doesn't seem to jive with real world experience. I don't think they way you are figuring this out is correct. Using an online calculator from http://hughestech.com/rc_calculator, I get the proper results which are about a second to charge up with the 2.2 microfarad capacitor and about 10 seconds with the 22 microfarad capacitor. Using your formula it would take almost a minute for the 22 microfarad cap to charge up. Even checking youtube videos of people showing the same circuit using the 2.2 microfarad cap, they get a flash about each second.

Note from the Author or Editor:
Page 85, printed edition, third para, delete sentence: "In this circuit, the capacitor takes about half a second to get close to 6 volts." Page 85, printed edition, fifth para, delete sentence: "The voltage drops back down, and the PUT returns to its original state." Instead please substitute this sentence: The voltage drops back down (although not to zero, so the ongoing cycle length cannot be predicted from the formula to establish the time constant).

JWulf  Dec 30, 2013  Feb 07, 2014
Printed
Page 85
end of 3rd paragraph

On figure 2-103, 2.2uF capacitor is in series with a 470K resistor. The sentence explaining the circuit reads: "In this circuit, the capacitor takes about half a second to get close to 6 volts", which is incorrect: t = 5RC = 5 * (4.7 * 10**5) * (2.2 * 10**-6) = 5.17 seconds I think if the book included the computation used to get the capacitor's charging time, the error would be much easier to spot. Experimentally, the LED in the circuit indeed flashes about every 5 seconds.

Note from the Author or Editor:
I'm not sure how we made this error, but so far as I can tell, the formula supplied by the reader should be inserted, and the text should be revised to state 5 seconds instead of half a second. Also, in the interests of not breaking pages, add a note to the right, using the THEORY style. The heading will say "Capacitor Charge Time" and the copy will say "The amount of time it takes for a capacitor to reach its threshold is calculated with 5RC, where R is the resistance (in ohms) of the resistor, and C is the capacitance (in farads) of the capacitor. So in this case, you'd multiply 5 by 470,000 by 0.0000022, which gives us 5.17 seconds." Line it up with the paragraph beginning "You may remember..."

Denis  Jun 21, 2010  Feb 01, 2011
PDF
Page 86
1st paragraph

The parenthetical in the second sentence equates 47 nanofarads to 4.7 nF. The "4.7 nF" was fixed from "47 nF" in a previous update, but the "47 nanofarads" was left unchanged. It needs to be fixed to "4.7 nanofarads".

Note from the Author or Editor:
I believe the reader is correct, but in my printed copy of the book, BOTH instances of 47 need to be changed to 4.7.

ChristianAllred  Mar 21, 2013  May 10, 2013
Printed
Page 86
Figure 2-104

In the circuit, L1 (Loudspeaker) needs to have its right-most wire shifted to the right and plugged into the right-most negative voltage column.

Note from the Author or Editor:
This is correct. The schematic should be modified.

James Floyd Kelly  Jan 24, 2010  Mar 01, 2010
Printed
Page 86
1st paragraph

The same error as on page 43 appears on page 86. The value of 0.0047uF is equal to 4.7nF, not 47nF as indicated.

Note from the Author or Editor:
I am puzzled that the reader describes this as "the same error." It appears to be a different error. In the first paragraph on page 86, 47nF should be changed to 4.7nF.

bruttium  Mar 30, 2010  Dec 01, 2010
Printed
Page 87
8th paragraph

The text states that the amplification of the 2N2222 transistor is 24:1, while the text and table on page 80 indicate it is 240:1. Correspondingly, the 500:1 combined ratio stated in the text should be changed to 50000:1 This seems to be a remnant of an earlier (and since corrected) error on page 80.

Note from the Author or Editor:
Please change penultimate paragraph on page 80 from "24 times the current" to "240 times the current" if it has not already been changed. On page 87, in the penultimate paragraph of the body text, remove the sentence "The 24:1 amplification of the first one is multiplied by another 24:1, giving a total amplification of more than 500:1." Substitute this sentence: "The 240:1 amplification of the first one is multiplied by another 240:1, giving a total amplification of more than 50,000:1."

Anonymous  Feb 13, 2011  Jul 15, 2011
Printed
Page 91
Figure 2-113

In the figure, C3 (Capacitor 3) should have its right-most wire shifted to the far right negative voltage column. The same problem exists for the jumper wire at the very bottom of the circuit; it needs to be extended one column to the right. (This jumper wire error is also found in Figures 2-107 and 2-109

Note from the Author or Editor:
The complaint is correct. The schematic must be modified as stated.

James Floyd Kelly  Jan 24, 2010  Mar 01, 2010
Printed, PDF
Page 96
under Essential: Helping Hand

On page 96 under Essential: Helping Hand - "model 64-2991 from RadioShack" should read "model 64-0079 from RadioShack".

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed, PDF
Page 97
under Essential: Clip-on meter test leads

On page 97 under Essential: Clip-on meter test leads - "RadioShack "mini hook clips", part number 270-372C" should read "RadioShack "mini hook clips", part number 270-372"

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed, PDF, ePub, Mobi, Safari Books Online, Other Digital Version
Page 101
last paragraph

Wrong RadioShack part number given for board shown in Figure 3-26. In the last paragraph on page101, second to the last sentence, where it states: "Cheaper options are RadioShack part 276-147 (shown in figure 3-26), or PC-1 from All Electronics." It should be: "Cheaper options are RadioShack part 276-149 (shown in figure 3-26), or PC-1 from All Electronics."

Note from the Author or Editor:
Delete "276-147" and substitute "276-149" as the part number has changed.

Chuck Eckenroed  Oct 15, 2013  Feb 07, 2014
Printed
Page 116
Last para of column 2

I suggest moving this para ("Point-to-point wiring is like...") to the end of #1. In the current location the reader expects it to be the end of #3.

Note from the Author or Editor:
I agree with the suggestion. On page 116, the last para in column 2 should be moved so that it is appended to the text in column 1. I think that's where it was supposed to be, and I speculate that the text was moved around because of design considerations.

Cary Swoveland  Oct 03, 2010  Feb 01, 2011
Printed
Page 117
First sentence of para 4 ("Look back...")

I suggest replacing the word "schematic" with "circuit" or "breakboard".

Note from the Author or Editor:
I agree, the word "schematic" should be replaced with the word "circuit" in the first sentence of para 4 on page 117.

Cary Swoveland  Oct 03, 2010  Feb 01, 2011
Printed
Page 118
3rd paragraph, 4th sentence

Replace "inside" with "instead".

Note from the Author or Editor:
The reader is correct. The error exists on page 188, in the third paragraph, line 3, last word in the line. Remove the word inside and substitute the word instead

Richard Callender  Jun 12, 2013  Oct 18, 2013
Printed
Page 118
Third sentence of first para ("R4 also is..")

1. "to so" should be "so". 2. Strike "though it". You cannot say the capacitor takes longer to discharge "through R4", because R4 was not present in the circuit being compared in Fig. 2-103. 3. It is not that the capacitor takes longer to discharge because R4 is 1K, but merely because a resistor has been added at that location. The size of the resistor only determines how much longer. Perhaps, "R4 is also 1K.", followed by a sentence explaining why it now takes longer for the capacitor to discharge.

Note from the Author or Editor:
Erratum 1: Text should be revised as suggested. Erratum 2: Text should be revised as suggested. Erratum 3: I hope the above changes should be sufficient to make the point clear.

Cary Swoveland  Oct 03, 2010  Feb 01, 2011
Printed
Page 118
figure 3-75

Voltage is not shown in figure 3-75

Note from the Author or Editor:
The report is valid. The voltage should be shown in exactly the same style as in Figure 3-76. The voltage shown in figure 3-75 should be 6VDC not 9VDC. The author has sent a new figure.

Anonymous  Sep 01, 2010  Feb 01, 2011
Printed
Page 130
Figs 3-89, 3-91 and 3-93, on p. 130, 132 and 133

In each of these figures, the relay is labelled "R1". This conflicts with it's labeling "S1" in Fig 3-95 on page 135 (which is required because a resistor is already labeled "R1". I actually don't think "R1" in the three schematics is referred to in the text. If it is not, you may want to just remove it from those schematics. If you keep the label, I suggest you change it to "S1" .

Note from the Author or Editor:
This is a "nonfatal" error because, as the reader says, the part is not referenced by the text. However, ideally the figures should be modified as the reader suggests.

Cary Swoveland  Oct 04, 2010  Feb 01, 2011
Printed
Page 132
Figure 3-91 caption

The caption references a missing figure number - should read "The self-locking relay depicted in [Figure 3-90] has been incorporated in the alarm circuit..."

Note from the Author or Editor:
James is correct; this will be fixed by inserting the words "Figure 3-90" as he suggests.

James Floyd Kelly  Feb 04, 2010  Mar 01, 2010
Printed
Page 133
Third paragraph

I found this paragraph difficult to understand. I presume "NO" means normally-open, but am not sure about that. Two expressions I did not understand are "parasitic capacitance" and "leakage currents of non-ideal elements".

Note from the Author or Editor:
Ironically this whole paragraph was copy-pasted into the book from our technical reviewer, who was addressing a previous error that he perceived. I think at this point I would simply insert the term: (normally open) after the first instance of the acronym "NO," because it has not been defined at this point in the book.

Cary Swoveland  Oct 04, 2010  Feb 01, 2011
Printed
Page 135
Fig 3-95

The 1K resitor R2 is not connected correctly; it goes between ground and one of the wires to the sensor switches.

Note from the Author or Editor:
The sensor switches ground the base of transistor Q1 through resistor R2. This resistor can be placed as shown in Figure 3-93 or as shown in Figure 3-95. The circuit should work either way. However, ideally the two figures should match precisely. Figure 3-95 should be redrawn for a future edition of the book.

Cary Swoveland  Oct 04, 2010  Oct 12, 2012
Printed
Page 140
2nd sentence of penultimate para ("S1 is a SPDT...")

Initially, I had a hard time understanding Figure 3-106 because I did not realise S2 had been spliced into the relay section of the circuit. I suggest you elaborate a bit, by adding something like this after the sentence I referenced: "I spliced S2 into the circuit by first cutting the two green wires that connect the sensor switches with the rest of the relay circuit. I then attached one pair of those wires to one side of S2 and the other pair to the other side, as shown in the figure."

Note from the Author or Editor:
This is not a serious problem but if there is room to make the change suggested by the reader, it should be incorporated in the book.

Cary Swoveland  Oct 05, 2010  Feb 01, 2011
Printed
Page 141
2nd sentence of penultimate para ("The transistor circuit...")

I suggest you change: "The transistor circuit..." to "The relay section of the circuit..." and "...to the transistor, keeping its base relatively negative." to "...to the relay section, just as before S2 was spliced in." The first suggestion is to make the wording correspond to the labelling in Fig. 3-106.

Note from the Author or Editor:
The text should be changed as the reader suggests.

Cary Swoveland  Oct 05, 2010  Feb 01, 2011
Printed
Page 148
Line 5, para 1

Change "...the two rows of pins on either side..." to "...the row of pins on either side..." (or "on each side").

Note from the Author or Editor:
The erratum is correct, and although it is not very important, the change suggested by the reader should be made in the next edition.

Cary Swoveland  Oct 05, 2010  Feb 01, 2011
Printed
Page 149
1st paragraph, last sentence.

Sentence: "For convenience we could refer to the first chip as a '74HC00' and the second chip as '74HC07' because..." Correction: '74HC07' should be '74LVC07', as mentioned in the previous sentence in the paragraph and as seen in Figure 4-3. -- This is otherwise an EXCELLENT book and a work of art. My thanks to the author and the team that put it together. I do not know any other book that even comes close to the quality of this book. A.M. Sabuncu Software Sr. Eng. amsabuncu@gmail.com

Note from the Author or Editor:
The error exists as stated, and the suggested correction should be made in the next edition.

Anonymous  Oct 23, 2010  Feb 01, 2011
Printed, PDF
Page 150
under "Here's your chip list:"

On page 150 under "Here's your chip list:", under "555 timer", please add "(part number 276-1723) after "RadioShack TLC555".

Note from the Author or Editor:
Approved

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 06, 2012  Feb 17, 2012
Printed
Page 150
before "LED numeric displays"

Experiment 19 needs 1 diode 1N4148 and experiment 23 needs 4(or 8). But it's listed in the "Shopping List: Experiments 16 Through 24". Better to list "Signal diode, 1N4148 or similar. Quantity: 5 minimum." before "LED numeric displays" at page 150.

Note from the Author or Editor:
This entails only a minor revision to the text, so let's do as the report suggests.

yehnan  Feb 14, 2012  Jul 27, 2012
Printed
Page 151, 179, 290
p 151, Second paragraph; p 179, penultimate paragraph, P 290, fig. 5-117

I think added clarification would be helpful for beginners regarding trimmer potentiometers. On the p151 /shopping list/, a written description (plastic box pkg, resistance adjustability with a tiny screw, higher capability of precision than resistors, introduce the term variable resistor) would be informative. A simple reference to the photo in fig. 5-117 (seen later in the book) would clarify that the trimpots do in fact look very different than the potentiometers learned about earlier in the text. Lastly, when the reaction timer project calls for the trimmers on page 179, there is no basic instruction on how to wire them. At some point you might also include explanation on what the third terminal/pin of pots are used for.

Note from the Author or Editor:
Since there is a lot of room to add some text on page 151, I would like to append the following text to the Potentiometers paragraph: A trimmer potentiometer may closely resemble a full-size potentiometer, except that it is miniaturized, with a screw head in the center, instead of a shaft. However, many trimmers provide greater accuracy by using a side-mounted screw that turns a concealed internal reduction gear. This type is shown in Figure 5-117. You can use either type for the experiments in this book, and the pins tend to be arranged similarly, with the center pin providing a variable resistance between the pins at either side of it.

Deborah  Nov 03, 2012  Dec 14, 2012
Printed
Page 161
Schematic

Capacitor C1 is labeled C4 in Figs 4-14 & 4-15. Capacitor C2 is labeled C3 in Figs 4-14 & 4-15. Capacitor C3 is labeled C5 in Figs 4-14 & 4-15. I suggest the same labeling be used in all three figures.

Note from the Author or Editor:
The reader is correct. In Figure 4-20 the capacitors should be renumbered to match previous figures 4-14 and 4-15. Since Figure 4-20 is for illustrative purposes only (and is not presented as a guide for the reader to build the actual circuit), this is a "nonfatal" error but still it should be fixed.

Cary Swoveland  Oct 13, 2010  Apr 29, 2011
Printed, PDF
Page 164
the first paragraph

In the first paragraph, "..the capacitor is connected from pin 7 to pin 2..." and "while removing the negative voltage from pin 7.". I think the pin number should be 6 not 7.

Note from the Author or Editor:
Amazing that this error was not reported before now. The two references to pin 7 in the first para of page 164 (first edition) should be changed to pin 6.

ethan kim  Jun 19, 2011  Jul 27, 2012
Printed
Page 165
Theory section, first formula

The formula as shown for frequency in the context of this Theory information is incorrect. It should read: Frequency = 1.44 / ((R1 + R2) X C1) or Frequency = 1.4 / ((R1 + R2) X C1) A similar formula appears on page 166, but it notes the resistance values are expressed in Kohms and capacitances in uF, so that formula works out. The formula on page 165 does not note special units. PLEASE stay with ohms, farads, volts, seconds, and so on. Using kohms and uFs in one formula and then somewhere else (and in other books) using ohms and farads will confuse people, particularly those just getting used to working with component values. The use of the formulas in this section is pedagogically unsound. Someone who looks at the formulas alone can go badly wrong. Also, the author should not use the constant 1.440 or 1440 because we do not have four significant figures in calculations with 5%- or 10%-tolerance resistors and capacitors. The author's table on page 166 provides values with one or two significant figures, so use two significant figures in formulas, too.

Note from the Author or Editor:
I am confirming the erratum. The first version of the formula supplied by the reader should be used.

Jon Titus  May 16, 2011  Jul 15, 2011
Printed
Page 165
Figure 4.25

Diode in schematic should read D1, not D2, to be consistent with explanation in the last paragraph on page 164

Note from the Author or Editor:
The label for the diode in Figure 4-25 should be D1, not D2. A substitute figure has been supplied.

Ken Wilson  Jun 30, 2014  Oct 31, 2014
Printed
Page 168
5th paragraph

The text states "the voltage detected by pin 5 slowly rises, so that the tone generated by IC2 gradually rises in pitch." This appears to be backwards, as a higher voltage on pin 5 would raise the required threshold voltage to trip the comparator. As a result, the charge/discharge times would be longer, resulting in a lower frequency, and hence lower pitch.

Note from the Author or Editor:
COnfirmed.

Jeff Schornick  Mar 27, 2011  Jul 15, 2011
Printed
Page 168
Figure 4-29

Figure 4-29 shows a schematic for a circuit that is supposed to flash four LEDs in sequence. The problem is that the when the 555 flips to negative output, which triggers the next 555, it will sustain the negative signal, causing the next 555 to stay triggered. For the schematic to work properly, it needs to instead send a pulse. To do this, there should be a capacitor in series between the output of one 555 timer, and the input of the next 555 that it is controlling. I learned this trick from experiment 18, and then was finally able to get the figure 4-29 circuit to work properly. Since this pulse trick isn't explained until later in the book, it would also be worth noting this in a footnote under the schematic. Ironically, this circuit is the one shown breadboarded on the front cover, and the missing capacitors are present in that picture.

Note from the Author or Editor:
The original circuit worked for me, and for my reviewers, but the behavior of 555s from different manufacturers may vary. Therefore I believe the suggested modification is a good one. This will entail a revised schematic and figure caption.

Stephan Westcott  Jun 19, 2011  Oct 12, 2012
Printed
Page 168
4th Paragraph

In the 4th paragraph, reference is made to figure 4-30. Later in the paragraph it is stated that the first timer in figure 4-30 will create an oscillating on/off output 4 times per second which I assume can be restated as 4 cycles/second.. Using the stated values of R4, R5 and C4 in figure 4-30 and the equation stated on page 166 yields 1440 / (( 1 + (2x10)) x 68) = ~1.0084 cycles per second which is the activity that I observe. If a value of 2.2 kilohms is used for R5, a value of ~3.9 cycles/second is obtained and is also what I observe. Maybe that's what was intended?

Note from the Author or Editor:
Easiest way to fix this: Page 168, fifth line in fourth paragraph: Delete the words "four times per second" and substitute "once per second"

John Robinette  Feb 19, 2013  May 10, 2013
Printed
Page 168
Figure 4-28

The resistor between the LED and ground should read R7 as R4 is already used for the resistor between pin 7 and the positive rail. This would also make the schematic agree with the bulleted note re: substitution of a 10k potentiometer.

Note from the Author or Editor:
In Figure 4-28, the resistor in series with the LED should be identified as R7. I have supplied a revised figure. No other changes are necessary.

Ken Wilson  Jul 14, 2014  Oct 31, 2014
Printed
Page 169
parts list for figure 4-30

The part list calls for a 0.047 uF polarized capacitor (C1). I assume this to mean it should have either an electrolytic or tantalum capacitor. Unfortunately, it appears electrolytics are not available in that small a valule and a tantalum capacitor at this value is priced at $18 CDN or better any place I've managed to find them listed. In reality, wouldn't any 0.047 capacitor work here, remembering to obey polarization if the particular capacitor requires it.

Note from the Author or Editor:
The schematics in Figure 4-22, Figure 4-25, Figure 4-26, and Figure 4-30 all show a polarized capacitor for C1. The reader is correct that for the value shown (0.047uF) a polarized capacitor is not available. However the parts list for Figure 4-21 does state "ceramic or electrolytic." Therefore a reader should be able to build this circuit. However, the schematics should be changed to eliminate the confusion. I have supplied new versions for the four figures. Also on page 163 in the parts list for Figure 4-21 omit the words "or electrolytic"

Ken Wilson  Jul 17, 2014  Oct 31, 2014
Printed
Page 172
fig 4-35

Are you sure that the OUTPUT-pins 14, 4 & 5 should be directly on ground? I have burned several 4026 until i learned that to much power is drown in this pins. This bug continues in the following figures. Regard, B PS: I realy like the refrehing style in which you explain the material. It makes fun to read. PPS: Maybe you could prepare an .pdf in which all confirmed error are listed, ordered by page number. It would be easier to check if there are known bugs, before starting a new project

Note from the Author or Editor:
The reader is correct. Pins 4 and 5 should not be connected to ground.

Anonymous  Sep 01, 2014  Oct 31, 2014
Printed
Page 177-179
starting last paragraph, pg 177

Switch labeling inconsistencies over pgs. 177-179: pg 177, last paragraph: "reset the count to zero (with S3)" should be S2. pg 178, end of 2nd paragraph: "taken the place of the start switch, S4..." should be S5 and change next sentence to "...get rid of S5, but keep the pull-up resistor, R10, ..." (up to this point S4 is the stop count, S5 is the start ) pg. 178, Figure 4-41: "Stop Count" switch should be S4. Need to relabel "Start Delay" switch to S5, I think. Under the figure, it lists "S1, S2, S3" which needs to be corrected anyway. So, text of pages 178-179 would need to be changed in a few places: S4 changed to S5 and S3 changed to S4 (Steps #1, 9, 10) and first two paragraphs of "Using the Reflex Timer". The final circuit works great, but I did get very confused with the switch name issue. If I'm wrong about all this, please let me know. This book is fabulous and that I can even figure out mistakes is a wonder. Thanks!

Note from the Author or Editor:
The switch numbering is inconsistent between figures, because each figure shows a modification to the previous figure. A significant rewrite over several pages, and relabelled switches, would be needed to fix this. I'm not sure it's worth it. This would be a compromise: On page 177, second para, second line, clarify it to read: as before, but when you press S4 (in Figure 4-40), it freezes.

Susan Auderer  Nov 27, 2011  Jul 27, 2012
Printed
Page 177
Figure 4-40

Figure 4-40 shows S5 connected to positive. As far as I can tell this doesn't work, because the intent is to send a negative pulse to pin 4 of IC6. The diagram should show S5 connected to negative. At least, that's what I had to change to get the circuit to work as described, and how I understand it working based on the Fundamentals description on page 176.

Note from the Author or Editor:
This report is correct. The left side of switch S5 should be connected to the negative side of the power supply, not the positive side. The schematic should be corrected. I apologize for the error.

Neil Enns  Jan 16, 2010  Mar 01, 2010
Printed
Page 178
Figure 4-41

In the figure, there are two resistors labeled R10, one between IC6 pin 4 and positive voltage, and another between IC7 pin 2 and positive voltage. The specified value for R10 is 1K ohms. When the lower resistor (the one connected to IC6) is 1K ohms, the start button didn't work for me. I had to replace that resistor with a 10K ohm resistor to get the start button to work.

Note from the Author or Editor:
Really we need a new version of Figure 4-41, as two resistors share the same identifier. However this fix will work for the time being. The caption to Figure 4-41 currently begins with this line: R7, R9, R10, R12: 1K Please break it into two lines that look like this: R7, R9, R12: 1K R10 (both): 10K The remainder of the caption should be retained as-is.

Andrew Dalton  Aug 08, 2013  Oct 18, 2013
Printed
Page 178
3rd paragraph under the "The Delay" subsection

In this experiment, C4 is a mystery to me. You state "The capacitor communicates the sudden change from positive to negative, but the rest of the time it blocks the steady voltage from IC7 so that it wont' interfere with IC6." Can you provide a little more explanation? I understand how it blocks the steady voltage from IC7, but how does it communicate the change from positive to negative? If I understand correctly, when the start button isn't pressed, C4 charges (positive on the side connected to IC6 pin4, negative on the side connected to IC7 pin3). After pressing the start button, both sides of the capacitor are positive -- what does that do to the capacitor? After the IC7 timer fires and the voltage on that side of the capacitor drops, what happens? Apparently it causes a voltage drop on the IC6-side of the capacitor --- enough to reset IC6 --- but why? Thanks!

Note from the Author or Editor:
On page 178 currently the third paragraph contains this text: The capacitor communicates the sudden change from positive to negative, but the rest of the time it blocks the steady voltage from IC7 so that it won’t interfere with IC6. Please remove that paragraph and substitute this paragraph: The capacitor blocks DC voltage from IC7 until pin 3 transitions from high to low, at which point this transition is passed through as a pulse to pin 4 of IC6.

Andrew Dalton  Aug 08, 2013  Oct 18, 2013
Printed
Page 179
4th paragraph after section title "Using the Reflex Tester"

The 4th paragraph discusses replacing the 68 uF capacitor C2 with a 1 uF one and the 2.2K Ohm resistor R8 with a 10K trimmer potentiometer in figure 4-41. It states that at the potentiometer's maximum resistance (10K Ohm), that this combination will generate 690 pulses/second. Since resistor R7 is 1K Ohm in figure 4-41, I can refer to the table on page 166. The frequency listed there for a 1 uF / 10K Ohm pair is 69 pulses/second, which is the behavior that I observe.

Note from the Author or Editor:
Page 179, fourth paragraph under "Using the Reflex Tester" subhead, delete the words "...and a 1uF capacitor..." and substitute the words "...and a 0.1uF capacitor..."

John Robinette  Mar 06, 2013  May 10, 2013
Printed
Page 180
1st paragraph

As follows from correction of the error in the next to last paragraph on page 179, the values of C2 under discussion shall be ten times smaller, i.e., 0.1 uF and 1 uF instead of 1 uF and 10 uF, respectivelly.

Note from the Author or Editor:
First paragraph of p180 should be changed to: First remove the 0.1 µF capacitor at C2 and substitute a 1 µF capacitor. Because you are multiplying the capacitance by 10, you will reduce the speed by 10. The leftmost digit in your display should now count in seconds, reaching 9 and rolling over to 0 every 10 seconds. You can adjust your trimmer potentiometer while timing the display with a stopwatch. When you have it right, remove the 1 µF capacitor and replace the 0.1 µF capacitor at C2.

David Antos  Dec 15, 2013  Feb 07, 2014
Printed
Page 182
Fundamentals, Paragraph #2

Wording should be "5-volt regulator" instead of "5-volt regular."

Note from the Author or Editor:
The reader's report is correct. Thanks.

Beth Lambert  Mar 08, 2010  Dec 01, 2010
Printed
Page 185
Figure 4-53

My book's Print History: December 2009 First Edition. Figure 4-53 now reads "The truth-table from can be relabled to describe the inputs and outputs of a NAND gate" After the word "from" and before the word "can", the following wording should be inserted. "Figure 4-52" After buying several other books dealing with electronics know-how, I can say this one is definitely worth every penny. It is a great starting point for those who want to go to the next level. Thank you.

Note from the Author or Editor:
The text should be corrected as the reader suggests.

Larry Gold  Jul 08, 2010  Apr 29, 2011
Printed
Page 194
Third bullet point

Reads: "The output from a logic chip can drive the trigger (pin 3) of a 555 timer." The trigger is pin 2, pin 3 is the output...

Note from the Author or Editor:
This complaint is correct (I don't know how anyone failed to notice this during the past year!) and (pin 2) should be substituted for (pin 3).

Darren Koepp  Feb 06, 2011  Apr 29, 2011
Printed
Page 200
Last paragraph

The last sentence on the page reads: "...compare the breadboard schematic in Figure 4-83 with the simplified schematic in Figure 4-84..." The figure references should be swapped swapped: Figure 4-84 is the breadboard schematic, and Figure 4-83 is the simplified schematic.

Note from the Author or Editor:
This erratum is confirmed. The references should be swapped.

Stephan Westcott  Jun 25, 2011  Jul 27, 2012
Printed
Page 201
Figure 4-84

There is an unlabeled resistor that is connected to keypad number 7... it's on the far right of the circuit near the top. I think it's supposed to be a 10K but not 100% sure.

Note from the Author or Editor:
James is correct, the resistor should be 10K.

James Floyd Kelly  Mar 18, 2010  Apr 29, 2011
Printed
Page 217
3rd paragraph in Theory sidebar

2nd sentence should read: "Figure 4-105 shows how the 74LS92 counts up from 0 to (decimal) 5 or (binary) 101 in its inimitable fashion." Change 6 to 5.

Note from the Author or Editor:
Correct, in para 5 of the Theory sidebar, 6 should be changed to 5.

James Floyd Kelly  Mar 25, 2010  Dec 01, 2010
Printed
Page 218
United States

The LED arrangement in the circuit in figure 4-107 and the spots on the dice in figure 4-108 do not match. In the circuit, high signals from outputs A and B light up the bottom left, middle and top right leds. In figure 4-108, high outpus from A and B show a die with the top left, midding and bottom right spots. While not incorrect from a technical standpoint, the dots/leds are reversed for the number 3.

Note from the Author or Editor:
The circuit does work but the depictions of dice with 2 spots and 3 spots are flipped left-to-right. A replacement for Figure 4-108 will resolve this issue. I have prepared the substitute figure.

Greg Ayer  Sep 20, 2014  Oct 31, 2014
Printed
Page 221
Figures 4-111 and 4-112

The schematic in Figure 4-111 and the photograph in Figure 4-112 do not match. The photograph has a resistor (10K ?) running from pin 1 of the 74LS06 chip to the negative rail. The schematic does not show this connection. Conversely, the schematic shows a connection from pin 5 to pin 9 on the 74LS06 chip which does not appear in the photograph. Also, the schematic shows several connections from unused pins of the 74LS27 chip to the positive rail which do not appear in the photograph. I have been unable to get the circuit to behave correctly with either configuration, nor a combination of the two. Any advice would be appreciated and thank you for this wonderful book.

Note from the Author or Editor:
The reader is correct that there are some small variations in wiring between the schematic and the photograph. However, they should not be crucial. The additional 10K resistor shown in the photo is to prevent the input of the inverter from "floating"; it is desirable but you should get results without it. The additional connections between unused pins and positive, in the schematic, are likewise good practice, but not essential to get a result. Without knowing more about the reader's circuit, I cannot advise him on why it isn't working.

Anonymous  Mar 04, 2010 
Printed
Page 221
Figure 4-111, 4-112

In Figure 4.111 you show pin 14 of the 74lS06 connected to the - rail. In Figure 4.112 you show pin 14 of the 741S06 connected to the + rail. I build the circuit against figure 4.111. The circuit does not function. I checked the TI data sheet and it shows that pin 14 of the 741S06 has to be connected to Vcc (+ rail).

Note from the Author or Editor:
It's surprising that this error was not reported by other readers during the past year, or by our fact checker or the people who test-built all the circuits. The complaint is correct and Figure 4-111 should be redrawn to connect pin 14 of the 74LS06 to the positive bus.

Joe Pitz  Dec 28, 2010  Apr 29, 2011
Printed
Page 221
Figure 4-112

The unused input pins of the 74LS27 and 74LS06 chips have been left floating in the photograph of the breadboarded circuit in figure 4-112.

Note from the Author or Editor:
This is correct, but there is no easy way to change the photograph at this point, and it's a minor issue.

Jasmin Patry  Feb 09, 2013 
Printed, PDF
Page 238
Figure 5-16 Caption

Please change "at far right" to "at far left."

Note from the Author or Editor:
Correct.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 12, 2013  Mar 15, 2013
Printed
Page 239
Parts list

On page 239, in Experiment 26, the parts list calls for "Signal diode, 2N4001 or similar." I believe that part number should be 1N4001, as listed on page 103.

Note from the Author or Editor:
This complaint is correct but I think the error has already been reported.

Justin Ting  Jan 23, 2012  Feb 17, 2012
Printed, PDF
Page 240
Last paragraph

Please change “Experiment 24” to “Experiment 25”, and “Experiment 25” to “Experiment 26”.

Note from the Author or Editor:
Correct.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 12, 2013  Mar 15, 2013
Printed
Page 249
half way down page

Book says we need 2, 47 microfarad nonpolarized capacitors but not shown on schematic on page 251. Book says we need 5 nonpolar 100 microfarad capacitors but the circuit diagram on page 251 only shows 2. It also shows a 10 microfarad nonpolar capacitor. The book on page 249 says we need a 100kohm potentiometer with audio taper but it is also not shown on the schematic on page 251.

Note from the Author or Editor:
The circuit was modified to change some component values, but the modifications were not copied back into the shopping list. They should be. (I am surprised no one noticed this in the past 3 years.) On page 249 please revise shopping list as follows: In paragraph specifying 47uF capacitors, omit 47uF and substitute 100uF. In the next paragraph, omit the first two sentences, through "Quantity: 5". Attach (run on) this paragraph, commencing with parentheses, from the end of the previous paragraph. Next paragraph, specifying potentiometer: Omit this paragraph. Add one new bullet-point paragraph on page 249, anywhere in the shopping list, as follows: Regular electrolytic capacitors. 100uF. Quantity: 3.

Ivan Rouse  Dec 04, 2012  Dec 14, 2012
PDF
Page 249
Shopping List

Although most problems were fixed in the PDF version, a 10 microfarad nonpolar capacitor is still missing from the shopping list and should be updated.

Note from the Author or Editor:
The reader is correct. Immediately below the photographs, the text reads: Nonpolarized electrolytic capacitors (also known as bipolar). 100 μF. Quantity: 2. This text should have a small insertion so that it looks like this: Nonpolarized electrolytic capacitors (also known as bipolar). 100 μF, Quantity 2, and 10 μF, Quantity 1.

None  Jun 24, 2013  Oct 18, 2013
Printed
Page 249
United States

The schematic on page 251 specifies .15 uF capacitors which are also not included on the shopping list. I don't think this is a common value so it might be worth a mention. I don't have access to the PDF version. Is it possible to restate the amended shopping list for Experiment 29?

Note from the Author or Editor:
0.15uF is a fairly common value, but yes, please add two of these capacitors to the shopping list.

John Robinette  Apr 18, 2014  Jun 13, 2014
PDF, ePub
Page 249
Shopping List

[This is a comment on the previous correction.] In the shopping list it says 2 non-polarized 100 μF capacitors and 3 polarized 100 μF capacitors are needed. However, in figure 5-41, in addition to the 2 non-polarized and 3 polarized 100 μF capacitors there is a 100 μF capacitor with ambiguous polarity connected to the power source, which I believe should be polarized. If so, then the shopping list should be updated to indicate 4 polarized 100 μF capacitors are needed.

Note from the Author or Editor:
The errror report is correct. The shopping list should be changed to list 4 polarized 100uF capacitors instead of 3.

Thomas Weisbach  Jun 02, 2014  Jun 13, 2014
Printed
Page 275
Fig 5-92 caption

Caption refers to Exp 31... should be Exp 32.

Note from the Author or Editor:
The caption should be modified as suggested.

James Floyd Kelly  Sep 18, 2010  Apr 29, 2011
Printed
Page 277
Figure 5-98

Regarding figure 5-98, I built this circuit at least 3 times using 5 & 12 volt relays of different manufacturers. The problem I encountered was most immediately apparent with the 5 volt relays but occurred with all attempts - triggering the switch would reverse the motor direction, but it would never revert to the original motion. I can offer no technical explanation for this. However, a Google search for "555 timer relay" yields a variety of simple circuits. The ones I inspected never fed the output of the 555 timer to the relay coil without diodes or transistors being involved. In fact this is how I solved my issue. I connected the collector of a 2n2222 transistor to positive voltage, the output of the 555 timer to the base and the emitter to the coil of the relay. I freely admit to being capable of repeating the same mistake 3 or more times, but perhaps this addition of a transistor could be mentioned to help readers that may have hit the same issue that I did.

Note from the Author or Editor:
I believe that if a diode is added across the relay coil, this should solve the problem. A revised version of Figure 5-98 has been supplied.

John Robinette  Jun 27, 2014  Oct 31, 2014
Printed
Page 281
1st paragraph in section "Mechanical Power"

I believe that torque is measured in Newton*meter in Europe, not dyne. Dyne is the unit of a force in the (obsolete) cgs system.

Note from the Author or Editor:
I believe this is correct..

Martin Hoecker  Aug 21, 2011  Nov 11, 2011
PDF
Page 286
Schematic

The schematic in the book did not work for me, even with all the components are recommended by the author. I believe wires from the motor must be connected directly to the 555 output from pin 3 rather than between the resistor from pin 3 and the LED. With the connection proposed by the author, the voltage is being sinked to negative through LED all the time for all wires, so the motor does not move. By connecting to the 555 pin 3 output, it will sink energy sometimes and sometimes it will source energy, generating the different states for each wire from the motor.

Note from the Author or Editor:
The error reported by the reader may only occur if certain LEDs are used. It should be fixed, though. On page 287, there are two indented paragraphs numbered 1 and 2. Since there is a lot of white space on this page, please INSERT an extra, new paragraph numbered 3. The text in this paragraph should be: 3. If you have trouble getting the motor to respond at all, try disconnecting the LEDs shown in Figure 5-108. Alternatively, try driving the four poles of the motor directly from the four outputs of the timers, instead of through 1K resistors. To verify that this is not overloading the timers, substitute a much higher value timing resistor for the 8K2 resistor, to slow the first timer to a 5-second pulse, and insert your meter, set to measure mA, between pin 3 of this timer and the load that it is driving. The maximum current must not exceed 200mA.

None  Jul 01, 2013  Oct 18, 2013
Printed, PDF
Page 295
1st paragraph

Delete first paragraph ("Figure 5-122 shows...of conductive foam.") Substitute this text in its place: The PICAXE 08M was the lowest-price chip in the range for many years, but was superceded more recently by the 08M2, which was a major upgrade. The 08M is still being sold from many suppliers, and the steps described in this chapter will work if you have that version. But if you buy the newer 08M2, that should work too, and will allow you to tackle more ambitious projects in the future. Figure 5-122 shows the features of the two chips as specified by the vendor, while Figure 5-123 shows a closeup of the 08M with its legs safely embedded in a piece of conductive foam.

Note from the Author or Editor:
Correct.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 12, 2013  Mar 15, 2013
Printed, PDF
Page 295
Figure 5-122

Please replace Figure 5-122 with this file: (This file may not be visible until Feb 13, 2013) http://examples.oreilly.com/9780596153755-files/new/mkel_05_122_new.png

Note from the Author or Editor:
Correct.

Brian Jepson
Brian Jepson
O'Reilly AuthorO'Reilly Blogger 
Feb 12, 2013  Mar 15, 2013
Printed
Page 299
Figure 5-131

My question regards Fig 5-131, the PICAXE test circuit. The resistor connecting pin 1 of the chip and the 330 ohm resistor has no numeric value. Is this an error, or is there a value for this component? It would seem to contradict the view in Fig 5-133. In fact, it would appear to short-circuit the battery or power source! Thanks for your help!

Note from the Author or Editor:
This error was previously reported and the schematic has been redrawn and submitted to the publisher for the next edition.

Anonymous  Jan 06, 2011  Feb 01, 2011
Printed, PDF
Page 305
the last item in the left column

In the book describes like this -- b2 and b3 use the same bytes as w1. -- b3 and b4 use the same bytes as w2. -- b5 and b6 use the same bytes as w3. -- b7 and b8 use the same bytes as w4. -- b9 and b10 use the same bytes as w5. -- b11 and b12 use the same bytes as w6. -- b13 and b14 use the same bytes as w7. It shall be changed to -- b2 and b3 use the same bytes as w1. -- b4 and b5 use the same bytes as w2. -- b6 and b7 use the same bytes as w3. -- b8 and b9 use the same bytes as w4. and so on.

Note from the Author or Editor:
Amazing that no one else noticed this in more than a year! The reader is absolutely correct, and the change should be made as recommended.

ethan kim  Apr 23, 2011  Apr 29, 2011
Printed
Page 309
2nd Paragraph

I have not worked with the PICAXE myself, but earlier in the book it is implied that the "pause" statement is followed by the pause-time in milliseconds. So I think that the sentence "pause for whatever number of microseconds" should be changed to "pause for whatever number of milliseconds".

Note from the Author or Editor:
Correct: It should be milliseconds. "Microseconds" was an error.

Martin Hoecker  Aug 21, 2011  Nov 11, 2011
Printed
Page 312
The line immediately above "finish:" in the code for the getkey routine

The line let b1 = 2 should read let b1 = 1

Note from the Author or Editor:
This complaint is valid. The error exists and should be corrected as suggested by the person who reported it.

Vincent Slyngstad  Jan 14, 2010  Mar 01, 2010
Printed
Page 313
Figute 5-147

The input to the ADC pin floats during the time when no button is actively being pressed. This will likely lead to erratic operation at best. A capacitor from the ADC input to ground might make this more reliable. Related issues are that the initial voltage is undefined, prior to the first button press. The code on page 314 can likely tolerate that, though. A more serious problem with the code on page 314 is that nothing prevents the program from reading the same key value repeatedly, as it is unlikely the operator can get his fingers off the buttons fast enough to prevent it. I'd expect the program to read a long series of "7"s, a long series of "4"s, and a long series of "1"s, in response to a correctly entered combination. Which would fail to unlock the lock.

Note from the Author or Editor:
These complaints are valid and I will have to rewrite a few sentences in the text and modify the schematic and the program listing. Pages 313 and 314 are affected. The floating input problem may be solved by adding a 10K or 20K resistor hard-wired between the power supply and the ADC pin, thus establishing a basic voltage, which should not alter the results significantly when buttons are pressed. However, this must be tested. The keybounce problem may be solved by adding a pause of a quarter second or half a second in the "finish" section of the program listing, to allow the user time to remove his finger from the button before the next keypress is detected. A more elegant solution would be to hold execution of the program by reading the ADC input repeatedly until its value changes to a number corresponding with "no key pressed." This would have to be done in conjunction with fixing the floating input problem, above. I will deal with these problems and will post a revised schematic and program listing. I apologize for the errors.

Vincent Slyngstad  Jan 14, 2010  Mar 01, 2010