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Re: magnetrons as diodes

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 05:25 PM 1/5/2007, you wrote:
Original poster: Ed Phillips <evp@xxxxxxxxxxx>

If you use the original microwave oven transformer, you can use the filament winding to heat the cathode like in the original configuration, and the case would be the anode of the diode. If the magnets were removed, I don't think the cavities inside would resonate, so I don't think microwaves would be produced. "

Absolutely right on both counts. Don't know what the voltage drop will be though. Certainly more than a string of 1N4007's or something like that but might be usable.

Might be a lot more robust than the semiconductor string. One advantage of old standard rectifier tubes like the 8020A is that they'll tolerate oopsies a lot better than a string of 50 1n4007s.

Given the basic design of the magnetron is as a moderate efficiency power oscillator, I'll bet it would handle the odd flashover or overcurrent or spike pretty well. The reverse voltage breakdown is probably in the 10 kV range, too. And, cheap to replace (as compared to the 8020As, which pretty pricey).

Easy to tell by energizing the heater and measure the voltage drop vs current with a DC supply.

Indeed.  Easier than firing it up at 2kV, too.  Good idea.