Modern Electronics (was Re: List charter mods & headcount... ;

From: Dwight K. Elvey <dwight.elvey_at_amd.com>
Date: Wed Jun 23 17:48:19 2004

>From: ard_at_p850ug1.demon.co.uk
>
>> > I know how, just about every part of, a microwave oven works and
>>
>> Then you'll know why the HV supply is almost invariably voltage
>> doubled AC and not rectified and smothed DC.
>
>I know it is (the magnetron itself is one of the diodes in the doubler,
>along with one capacitor and a semiconductor diode), but I don't actually
>know _why_. Presumably it's to simplify the insulation of the transformer
>or something.
>
>-tony
>

Oops
 I missed this question. Tony is right. Also, once the
magnetron gets to the threshold voltage, it likes to
run at a constant volage. The capacitor source is
better at supplying this as part of the sine wave.
If you try to feed it with a fixed voltage, it will
destroy the tube. The capacitor works like a current
limiting resistor without the power loss.
Dwight
Received on Wed Jun 23 2004 - 17:48:19 BST