We found this circuit in a Radio Electronics from April 1965. The components are from the time and the power supply is for 12 V cars. The transistor must be equipped with a good heat radiator.
This interesting source of very low voltage for reference finds applications in the...
This sonic switch, sound relay or simply vox uses a medium impedance speaker as a microphone. The...
Using red LEDs with ignition voltages of the order of 1.5 V we can make a multiple voltage...