We found this battery eliminator in a Radio Electronics magazine from August 1974. The transistor must be equipped with a heatsink and other voltages can be achieved by replacing the zener.
The circuit shown has a voltage gain of 500 times and can use equivalent FETs like the BF245. The...
Found in a 1968 Novel Electronics Circuit, this circuit compares two light intensities using...
We found this circuit in an old publication from Argentina. The relay must be of the sensitive type,...