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 silencer or squelch preamp circuit was found in a documentation for radio amateurs. It...
This circuit was found in a 1994 publication. It draws 1 of 41 LEDs when we press and then release...
This circuit makes use of a diac to stop the activation of a sensitive reed relay 1 mA. The trip...