Re: Resistor vs transformer

On Tue, 07 Feb 2006 22:51:00 +1000, Peter Jakacki
<peterjak@xxxxxxxxxx> wrote:

Hi Hans, I see you have had some helpful replies ;) I take it the 120W
was a typo as you just mentioned 6W and you probably meant 120V drop
(230V-110V). If you do want to use a resistor instead of a transformer
it is best to use a series combo of a resistor and a capacitor. But
before I go any further I should state that I wouldn't recommend this
approach for anything but low-power non-isolated applications. You might
use this if you just needed 10 to 20ma such as in some line-powered
triac circuit.

It is true that a capacitor can be used instead of a resistor but you
have practically no current limiting when it comes to transients, they
will just pass right through the cap and let all the magic smoke out of
your components.

But I think that you probably need to detail your application a little
better because it may be that a transformer solution could be better
suited, but of course this depends upon your load. I sure if you provide
more detail, that among the many replies you may find one you can use.

*Peter*

You are right I meant 120V .
Thanks and all those who gave "useful" replies.
Its a wireless receiver unit which calls the fire department in case
of a fire.

Hans
.

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