Operated directly from the power grid, this detector was found in an 80's RCA documentation. The sensor is an ionization chamber. The SCR triggers a warning siren.
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...