Start circuit for microwave oven

Abstract

A start circuit arrangement for a microwave oven including a power control relay circuit which is independently responsive to a user actuable momentary start switch and to a programmed electronic controller to facilitate operation in a delay start mode. The relay circuit includes a start latch circuit, a door switch and an arm switch. User actuation of the momentary start switch sets the latch circuit. A signal from the electronic controller resets the latch circuit. The door switch is closed by closure of the oven door. The arm switch is closed by an arm signal from the electronic controller when an actual cooking cycle is to begin. The arm signal is removed upon expiration of the cooking cycle. The arm switch, start latch means and door switch are all operatively coupled to the relay such that the relay only enables energization of the power circuit for the oven when the arm switch and door switch are closed and the start latch is set. In the time delay mode, the latch is set by actuation of the start switch following entry of the operating mode and time information. At desired start time the arm signal from the controller closes the arm switch enabling energization of the source of microwave energy as well as the blower, the oven lamp, and the mode stirrer motor.