Filament source (T398E)

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

Light Sensor (CB5973E)
This circuit can use any comparator or even an operational amplifier. We can use the LM339 and the...
Ultra Precise Delay Circuit (CB5152E)
This circuit is from an 80's American documentation. The circuit uses components of the time which...
Operational Pulse Generator (CB19092E)
The pulse duration is determined by the 100k resistor and the separation by the 1M resistor. The...