This CMOS integrated alarm was found in the July 1992 Radio Electronics magazine. The circuit has a small power stage and its sensitivity is adjusted at R5.
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...