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.
The sensor of this circuit consists of two 1N4148 diodes connected in series. The accuracy of the...
This setting appears elsewhere on this site. This was obtained from an 80's Circuit Encyclopedia and...
This circuit can be used as a direct optical link or by optical fibers. We found it in a...