Importance

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Abstract

There is disclosed a two-wire (series connectable) delay-on-release timer apparatus for air conditioner compressor motors or the like which is connectable in series in one side of the alternating current circuit with a low voltage alternating current source, a thermostat switch with a shunt resistor acting as an anticipator heater and a relay, or other control, for applying power from the power main to an air conditioner compressor or the like. The timer includes a full-wave rectifier circuit with output connected to an adjustable time delay digital timer and also connected to a gated thyristor whereby turning the thyristor on greatly reduces electrical impedance between the input terminals of the rectifier circuit. A digital timer IC is provided with circuit elements for sensing the difference between thermostat switch closed and thermostat switch open conditions. The digital timer IC is configured to start when the thermostat switch opens and after it times out and the thermostat switch closes, a signal is provided to trigger the thyristor and produce high conductance for the rectifier circuit to operate the relay and supply power from the power main to an air conditioning compressor or the like. Power failure also resets the timer so that turn on after a power failure is delayed for the time set by the particular timer.

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First Claim