RF or even switching transistors like the 2N2222 can be used in this circuit. The capacitors are ceramic and the frequency is determined by the crystal.
This circuit controls a heating element with voltage from 6 to 30 V and current up to 3 A from...
Indicated to operate in tube circuits, this preamplifier has 250 V power supply. The circuit is...
We found this circuit loader in a French magazine Electronique Radio Plans from July 1993. The...