This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM backup battery. Resistor R1 determines the battery charge.
We obtained this circuit from an old Argentine magazine. The circuit originally uses germanium...
We found this circuit in an old English publication. The sensor is a common LDR. and the...
This circuit is from an 80's component manual. The components are from the time, but the circuit...