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.
May 2017 - Panasonic's new APS1 series of optical couplers with 3 750 V insulation and up to 50...
Found in an EDN from the 90s, this circuit uses an electret microphone. The output can be used to...
The purpose of this circuit, found in a 1994 documentation, is to provide resources for testing...