[Lowfer] Another power supply 'head scratcher'

[Bill Ashlock]

To the group,

I just now located a number of microwave schematics on the Web and it looks like the safety problem is not what I thought. When I first looked at my oven it appeared that the secondary of the HV transformer and magnetron were connected to the neutral side of the power input and the diode to the chassis (and of course the on board schematic showed all connected to the neutral side). This is not the case as the low side of the transformer, the magnetron, and the diode are all connected to the chassis - and this posses no danger as long as there is sufficient isolation between LV and HV windings of the transformer. Think of this as an older TV with metal case. The 15 to 30KV going to the CRT from the flyback and HV diode uses the chassis as the return and posses no danger to someone touching the chassis because there is no HV current path to ground.

Thanks to all that commented on my 'head scratcher'.    

Bill