Abstract: A method of triggering a controlled rectifier to ensure that it conducts fully and remains conducting for a required time, comprising supplying to the control electrode of the rectifier a large amplitude pulse with high transductance per unit of time to initiate conducting, and a small amplitude signal to maintain conducting. A circuit for producing such a pulse and signal comprises a pulse generator and a blocking oscillator both controlled by a control generator.

Abstract: A control circuit for controlling a supply of D.C. voltage to the input of an inverter. The circuit includes a control arrangement and apparatus for adjusting the D.C. voltage supply in accordance with signals applied to the control arrangement. The circuit also includes a current sensor for sensing the current supplied to the inverter, a sensing device for an A.C. voltage component connected across the input to the inverter, and apparatus for applying signals to the control arrangement in accordance with the current sensed by the sensor and the A.C. voltage component sensed by the sensing device.