This 4-tube circuit was found on a Radio Craft from December 1945. The circuit has excellent sensitivity. Power comes from a power supply with a transformer.
This timer uses common components today. It activates a relay after intervals that can be adjusted up...
September 2016 - It can be obtained from Mouser Electronics the new ADC AD7779 from Analog Devices with...
Found in Popular Electronics from the 90s, this circuit consists of a timer that turns off the...