Goldstar MA-2005ST service manual Input Senondary Winding AT

4-3. WARNING - High voltage circuit ( 4,000 volt )

INPUT + -

+

	SENONDARY￿
	WINDING AT￿
	2000V
-	MAGNETRON

INPUT + -

-

	SECONDARY￿
	WINDING AT￿
	2000V
+	MAGNETRON

*The half-wave voltage doubler circuit consists of the secondary winding of the high voltage transformer, H.V. diode (rectifier), and H.V. capacitor. The H.V. diode allows alternating current (AC) to flow in one direction only and rectifies it to pulsating direct current (DC).

The H.V. capacitor is able to store energy on one half of the AC cycle and release it on the other half cycle.

*During the first half cycle of operation, the secondary winding of the transformer supplies 2000 Volts to the capacitor current flows through the diode and returns to the transformer for a complete circuit. This half-cycle of AC charges the capacitor to approximately 2000 Volts.

*During the second half cycle of operation, the current flows in the opposite direction, again supplies 2000 Volts to the circuit.

*This permits the capacitor to discharge its 2000 Volts on top of the 2000 Volts generated by the secondary winding, creating an approximate total voltage of negative 4000 Volts D.C.

The negative 4000 Volts DC causes the magnetron to conduct current and, to oscillate at 2450 MHz.

The first half cycle and the second half cycle become one complete cycle, repeated input power frequency times per second .

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