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Old December 6th 11, 09:27 AM posted to rec.autos.makers.vw.aircooled
tricky[_2_]
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Posts: 50
Default preheater troubles



On 05/12/11 21:32, davygrvy wrote:
> Why any heater wire at all? What if I could just bolt a 15 amp
> (TO-3P) transistor right to the manifold itself and cook the metal
> directly? Hopefully there's enough material to grind a flat. Using a
> PNP transistor, collector is at ground potential so no need for any
> mica insulation.
>
> https://www.facebook.com/photo.php?f...e=1&permPage=1



Remember, with the transistor fully on, there will be little voltage
drop across it. Therefore there will be little power dissipation. ...
Little heat .

you need to bias it half way between the rails to get the most power /
heat, out of it.

It's early, so I might have missed something there ! ...

Like I said on FB, a plain old power resistor would be much simpler

Rich
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