Voltage amplifier with the 37 tube (T392E)

Found in a modern design book with tubes, this stage with the triode 37 has a plate current of 3.7 mA.

CMOS 4001 Alarm with Latch (CB24374E)
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
Alarm System (CB16793E)
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
Light Activated Alarm (CB26164E)
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...