We found this circuit in the September 1995 issue of Electronics Now magazine. The circuit has 6 scales for resistance measurements and uses an analog indicator from 50 uA to 1 mA.
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...