Make: Radio

243Appendix D: Understanding Oscilloscopes

Now, let’s suppose you change the scale on the screen so that you zoom in

on the signal, as in Figure

D-9

. The voltage represented by each interval on

the vertical axis has doubled, while the elapsed time represented by each

interval on the horizontal axis has decreased by a factor of 5,000.

Maybe you have read in the past that a 555 timer generates a voltage spike;

well, now you can see it for yourself. The 555 output that looked like a nice,

sharp square wave turns out to reach almost 15V before it gradually flattens

out. Although the disturbance is brief, it can confuse other components in a

circuit. ...