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We found this circuit in the November 1992 issue of Radio Electronics magazine. The 30V power supply must be symmetrical and preamplification stages are included.
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...