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.
This circuit was found in an EDN from the 90s. The circuit employs a double 555 and uses the...
This very common high resistance input voltmeter configuration was obtained in a 1993...
If the player is recovering an old cassette recorder and needs a preamplifier to pass recordings from...