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Panasonic Microwave Oven Inverter HV Power Supply

Nearly all Panasonic microwave ovens now use an Inverter, and are always labelled with “Inverter” on the front. The High Voltage Power Supply Unit (HV PSU) The HV PSU measures 165mm x 105mm x 60mm and weighs 650g.  At left is the control daughter board. In front of that on the main board are the opto-isolators for the control and status signals brought out to the green connector. Back left is the rectified mains filter choke. The mains rectifier and switching transistors can just be seen on the heatsink behind the transformer. The mains filter capacitor is at right rear. The HV rectifiers and filters (doubler) are right front – white wires are the HV output from the transformer. The green wire is for grounding the HV +ve. The two lugs t right are for connecting HV -ve and heater to the magnetron. The winding thatcan be seen on the transformer is the primary and is made from 3mm finely stranded wire. Here’s a view of the control end:  This is the high voltage end: The circuit f...

DC DC HV Boost Converter

A boost converter works in two stages, ON and OFF. In the ON stage the Semi-conductive Switch is conducting and current builds up in the inductor producing an electromagnetic field, this field stores energy. In the OFF stage the Semi-conductive Switch does not conduct and the electromagnetic field collapses. When the field collapses the energy stored in it can not escape through the Semi-conductive Switch so it goes through the diode and into the load/Capacitor at a much higher voltage. This happens several thousand times a second via the pulses from the NE555 Timer Chip and the result is being able to charge a high voltage capacitor from a low voltage source. Below is some aid for those of you who do not know electronics well. [ ]