This circuit with two operating modes was found in the September 1989 issue of Radio Electronics magazine. Other operational amplifiers can be used. The power supply must be dual.
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...