This circuit is from a 90s documentation. It has a hysteresis and uses a light sensing bridge. The circuit generates a 1000 Hz modulated 10 Hz signal. The signal must be applied to an amplifier.
With two cascading tunnel diodes, this circuit found in a 196 General Electric documentation...
Found in General Electric's 1969 documentation, this circuit uses two Foto Darlingtons to control...
This circuit is used in the analog part of the telephone lines. The same circuit can directly...