Found in 90s Popular Electronics, this circuit fires a load through a MOSFET from an audio signal applied to the input. Power supply is done according to the load.
We found this circuit in an American documentation from the 60's. The transistors are made of...
The accuracy of this circuit depends on adjustments made with capacitors of small tolerances of known...
The figure shows how to implement an OR function with two inputs, using a relay. The relay...