We found this circuit in the December 1968 issue of Radio Electronics magazine. The circuit is used with high-impedance magnetic headphones. The transistors are from that time.
This VCO makes use of an RC4558 which is an operational amplifier with characteristics close to...
This circuit can operate with different voltages, depending on the zener used. We found it in a...
This circuit can be used in the car to control the windscreen wipper or with other appliances at...