A record of mistakes in the printed book, mostly noticed by readers (thanks!). See something? Say something. I’ll post it here:

“I’ve been using your book to teach second graders about motors and circuitry and noticed an error in the diagram on page 160. I notated it below- it appears one leg of the potentiometer connects to ground when it should attach to pin 2 of the 555 timer. It is correct in the photograph and the instructions.”
– Mark Kleeb


“…the formula for numbered screw diameter calculations found on page 53 should use 0.06 and not 0.073.”
– Bill Ryder