This cassette player motor speed control was found in the January 1991 issue of Radio Electronics magazine. The circuit is for voltages from 9 to 12 V.
Using bipolar, FETs and unijunction this long-lasting timer can reach 10 hours with good quality...
This 1-transistor circuit for currents up to 50 mA was found in the August 1974 Radio Electronics...
We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the...