hello Dave et all,

>No one ever said you can't use MOSFETs on AC; you just have to be a
>little clever, is all.  Usually, that means you end up having to use two
>of them in series-- one for each half-cycle-- because of the intrinsic
>body diode that shunts the drain and source.
>The circuit below uses no voltage-dropping, power-wasting TRIAC, no
>likewise bridge rectifier, no relay^H^H^H^H^H "electromechanical logic",
<snip>

    this circuit is really very interesting. I've tried it with low current
(about 200mA) at 30VAC and worked like a charm. I'll try to use it with
something that requires more current to see how it works.

    Now, how about using an IGBT? I'm thinking of using this circuit to make
reverse dimming control (a topic that was discussed last year) in 100-240V
and I'm afraid I will burn some MOSFETs. Maybe IGBT would be a better
solution as they're made for high voltages, but the only way I can think is
to put the IGBTs on the MOSFETs place on your circuit and use a pair of
diodes. But then we'll have a large voltage drop.

    Have someone tried anti-paralleling IGBTs?

    Best regards,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Researcher and Developer               Blumenau  -  SC  -  Brazil
Say NO to HTML mail                          www.citronics.com.br
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