Errata

On page 87, Experiment 10 "Transistor Switching", in the section titled "You Will Need", one of the items listed as need is a "1uF capacitor".

However, throughout the experiment, the only capacitor I see being used is a 1000uF capacitor. Figures 10-17, 10-18, 10-21 and 10-22 show a 1000uF capacitor.

I assume this was an error in the "You Will Need" list, and it is minor, but I wanted to make you aware.

Re: my earlier report, capacitors C7 and C9 are actually correctly shown as 100 microfarads, so the issue is just with the values for the RC networks (R3 / C1 and R8 / C5), with a combination of 10 microfarads and 47k giving a charging time of just 0.47 secs or 4.7 secs with the 470k resistor substituted. So I believe these capacitors should be 100 microfarad as well.

The description for the 16-gauge Wire says it is "for the antenna in Experiment 31" - however it is for Experiment 28.

long ignore =0;
should be
unsigned long ignore = 0;

Since millis() returns an unsigned long, which is compared to and assigned to ignore, ignore should be of the same type.

"The six letters and symbols in the top half of Figure 1-4 are often preceded by multipliers. "
Which are actually shown in the top half of Figure 1-5.

The circuit diagrams for the alarm circuit show two 10 microfarad capacitors in the RC networks for IC1 and IC2 and two 100 microfarad capacitors connected to the the reset pins of IC2 and IC3. I believe these have been accidentally transposed in the drawings. The 100 microfarad capacitors should be in the RC networks for IC1 and IC2 while the 10 microfarad capacitors should be connected to the reset pins of IC2 and IC3. This error will not stop the circuit from working, but it will mean that the timing is not correct (it will be closer to .3 of a second for 47k resistors used in testing and 3 seconds for 470k resistors used in final circuit, when it should be 3 seconds and 30 seconds respectively).

The paragraph describes with certainty that the display showing 0 has to be an issue with the timer, or the wiring from the timer's output to the 4026B chip. However, I have encountered a different situation - which kept me searching for quite a while! - which can cause the issue: R10 being connected to the positive bus instead of the negative one. It may be helpful to others to acknowledge this in the book.

In the above paragraph it is stated categorically that the counter staying at zero is due to an issue with the wiring of the 555 timer, or with its connection to the decade counter.

However, I encountered another possibility. In my case, the value pull-down resistor R10 (10k Ohms) connected to the reset pin of the 4026B was not correct. Reducing the value of the resistor to 4.7k still did not work, but a 1k resistor did.

I'm not sure why this is - perhaps the specification of the chip varies slightly for different manufacturers? However, it took my some time to find this error in my circuit so it may be worth highlighting. The existing text encourages the reader to focus on wiring errors, which may put their attention in the wrong area.

The very last paragraph of the page reads "In Figure 23-3 you can see that Pin 2 of the timer, which
is the Reset Pin[...]". It should read "In Figure 23-3 you can see that Pin 2 of the counter, which
is the Reset Pin[...]". Awesome book so far, Charles! Best Regards!

Figure 23-7 on page 222 shows 74HC32 but it should be 74HC393