On Mon, 18 Feb 2002, Spehro Pefhany wrote:

> At 11:05 PM 2/18/02 +0000, you wrote:
> >The circuit below uses no voltage-dropping, power-wasting TRIAC, no
> >likewise bridge rectifier, no relay^H^H^H^H^H "electromechanical logic",
> >and allows you to control your lamps either ON/OFF with a logic level
> >from a PIC (might want to boost that up to a little higher than 5V,
> >unless you use logic level FETs), or control lamp brightness with the
> >PIC's PWM.
> >
> >            0--------------------------0
> >
> >         FROM 12V                  TO LAMP
> >         XFORMER                    STRING
> >
> >            0------+           +-------0
> >                   |           |
> >                   |           |
> >                   |           |
> >                   |           |
> >                   D           D
> >               Q1    G---+---G    Q2
> >              Nch  S     |     S  Nch
> >                   |     |     |
> >  GATE DRV  0------------+     |
> >                   |           |
> >                   |           |
> >  PIC GND   0------+-----------+
> >
> >Voila...
>
> Very nice, Dave! A couple of IRLZ544's maybe. They would have
> a total drop of about 1.1V at 20A, so about as good as a triac.
> At 10A, they'd beat it by a mile.
>
  eh, eh you have too rested minds guys !
  This will never work, take a look better ...

  So, people said: relays, triacs, bridge and tranzistor ( the best
solution here ) other "ingenious ideea" which does not take care of
polarisation and the fact that not every time a mos-fet can be used as
a controlled switch.
  What about a transformer magnetic amplifier ? Does any of the youngest
to project such things ?

  Dale, take care about the iminent distruction of the bulbs filament at
high current off ( bulb totaly cold ) - on switch

best regards, Vasile

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