Switching voltage source for TV receiver tuner - has switching transistor in oscillator circuit acting as switch and delivering voltages

摘要

A positive voltage is applied to the anodes of switching diodes in one reception range, and a negative voltage in the other range. The positive voltage is switched by a switching transistor. The switching transistor is provided in an additional oscillator circuit and acts in one range as a switch for all switching diodes except the oscillator switching diode, and delivers the positive voltage, while in the other range it delivers the negative voltage. It oscillates in a self-excited oscillator circuit, whose rectified voltage is the negative voltage. Positive and negative voltages for the oscillator diode are supplied directly from the range switch voltages.