Audio Cable Tester (CB3827E)

This simple circuit tests both monophonic and other two-wire audio cables. The circuit is powered by two common batteries.

LED Binary Counter (CB4345E)
This circuit came out in an American magazine that no longer exists. It's the Electronic...
Code Switch (CB10287E)
This circuit originally came out in a Budget Electronics from 1981. The American magazine no...
LM382 Preamplifier (CB15083E)
This is the traditional audio preamp configuration with the National Semiconductor LM382. The...