> robertf wrote:
>
> >Hello,
> >
> >I was working on a timer ckt
> >on top of the microwave oven
> >in the kitchen( only place
> >with grounded outlet) when the
> >wife needed to use it. My
> >voltmeter was on top and it
> >started giving me a reading of
> >about a few tenths of a volt.
> >The dvm lead was just lying
> >over the top of the door. This
> >caught my attention and I
> >started to run the leads
> >around the door seal. It reads
> >when the leads are by it and
> >no reading when I pull it
> >away.  Does this mean it is
> >leaking?
> >

Thomas C Sefranek wrote

> Probably not, I'd guess you were measuring the magnetic field of the
> power transformer.
> You meter has almost no chance of detecting the frequencies of the oven.
>
> >
Sorry to disagree. but any electrical non-linearities within the measurement
system can cause the meter to register a microwave signal. The Microwave
signal bathing the inside of a microwave oven consists of a 2450 MHz carrier
pulsed at your line frequency 50 or 60 Hz. Old microwave ovens are
particularly prone to leaky door seals And rusty self tapping screws, purely
as part of the wearing out process. It is possible for the rectified
Microwave leakage (Rust Bolt Effect) to be of sufficient power to register
on the unconnected leads of a high input impedance dvm.

If I was you I would play it safe and get your oven checked out for leakage.

Regards

Chris Carr

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