This sensitive circuit was found in the June 1995 Electronics Now magazine. R1 can be from 10k to 1M depending on the desired sensitivity. Power is supplied by the relay.
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...