Microwave oven power supply and oscillator therefor

Abstract

The specification presents an improved microwave oven power supply of the type which contains a transformer having a primary and high voltage secondary winding, a rectifier and capacitor combination connecting the high voltage secondary winding to a microwave magnetron and a control switching means, such as a Triac, is included in series circuit with the transformer primary to control current through the primary. In combination therewith a pulse generator is employed to control the operation of the switching means; providing voltage pulses to the switching means essentially to turn the switching means on and off for predetermined intervals. The improvement provides in the combination a pulse generator that contains a single control member accessible to the user, which varies or adjusts the width or duration of the pulses applied to the control switch means and concurrently varies or adjusts the time base or time period in which such pulses reoccur, suitably expanding the pulse duration concurrently with expansion of the time base, and vice versa. In an additional novel combination a synchronizer and an AND gate are connected in circuit with the pulse generator so that the concurrence of a synchronizing pulse from the synchronizer and a control pulse from the pulse generator must coincide in time before the Triac control switch means may be started.