Filament source (T398E)

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

Burnt out lamp Indicator (CB6327E)
This circuit was found in a 1964 Electronic Design to indicate when a headlight or flashlight bulb is...
Negative Edge Differentiator LM3900 (CB15256E)
Other amplifiers of the series like the MC3301, MC3401 and LM2900 can be used in this circuit. We found...
Diode Test with Oscilloscope (CB4160E)
The circuit shown enables dynamic diode testing with an oscilloscope. We found this configuration in a...