Found in a Popular Electronics from the 1990s, this circuit monitors the voltage of a power supply or battery. The trigger voltage is adjusted with a potentiometer.
Capacitance to voltage converter (CB6075E) This Texas Instruments circuit can be used on a...
The signals from this circuit obtained from the 1965 Radio Shack documentation are picked up from...
Found in Popular Electronics from the 1980s, this circuit uses two operational amplifiers from...