Re: Re charged insulators

[brian whatcott <inet@intellisys.net>]

At 16:12 7/7/98 -0400, you wrote:

> Suppose a properly selected plastic insulator is volume-electrified as
> above and allowed to solidify. You will have a permanantely charged object
> with interesting properties. For example, a positive "pith ball" of 0.001 C
> and a negative one ...  And not only for classroom demos. A patentable
> project anyone?
> ...
> Ludwik Kowalski


Such a device is called an electret microphone. (Similar at least - 
the electret material is simply subjected to a high electric field 
before solidification)

There has been at least one piece in SciAm on electrets ( named by 
analogy to magnets)

Brian Whatcott    Altus OK