Filament source (T398E)

Despite being transistorized, this is a constant current source circuit for 1 V valve filaments such as the 1H4 tube.

Pulsing Tone Alarm (CB4878E)
This variation of the previous circuit produces a pulsating sound when the sensor is activated. The...
PUT with 2 Transistors (CB4216E)
The circuit shown simulates a programmable unijunction transistor (PUT). Transistors may be common...
Quinary Trigger (CB6805E)
Suggested by an American publication, this circuit has 5 operating conditions indicated in the...