Filament source (T398E)

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

CMOS Alarm (CB25947E)
This simple alarm circuit was found in the May 1990 issue of Radio Electronics magazine. The...
Damped Percussion Oscillator (CB12084E)
This circuit was obtained in a 1978 publication. The operational amplifier must use a symmetrical source....
Neon Lamp Driver (CB11014E)
This circuit is from an Electronics Now, American magazine from December 1992. The magazine no...