This old 4-channel circuit was found in the December 1994 Electronics Now magazine. The circuit uses a 556 as a modulator. Note the code programming key.
This sound effect circuit is from a Radio Electronics magazine from December 1969. The transistors...
This few-watt amplifier was found in the August 1975 issue of Radio Electronics magazine. The...
We found this simple test of zener diodes in a 1978 publication. The potentiometer can be...