This circuit was obtained from Electronics Now magazine, July 1995. The triac depends on the heating element current, and the sensor will determine the adjustment potentiometer.
Found in a 1967 Electronic Design, this transistorized circuit compresses and then expands a pulse....
This squelch is activated by its own noise, acting automatically. It is used in communications...
This is the battery-powered version of the previous circuit. The circuit is from the same Radio...