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.
This circuit is suitable for modulating small FM transmitters for eavesdropping or espionage. The...
This circuit trips with negative pulses and the value of C depends on its intensity. C1 determines the...
The integrated circuit is not common nowadays since the configuration was obtained in Motorola's Linear...