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Re: coil running of car battery(s)?

Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Hi Derek,

Well unless they have some protection or they have come up with a new gate
material yep that's a quick way of killing them one very narrow spike will
do it on the gate.
The older power fets did not even like a spike on the output.  I assume this
one avalanches in a controlled fashion just soaking up the joules over the
whole die.   Still 1/2J is impressive assuming I did not miss read the spec.

Robert

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, January 24, 2005 4:21 PM
Subject: RE: coil running of car battery(s)?


> Original poster: "Derek Woodroffe" <tesla@xxxxxxxxxxxxxxx>
>
>  >Hi Derek,
>
>  >I was curious about the circuit so I checked it out. I was initially
> concerned because it has no snubber >
>  >across the FET.  So I checked the data sheet out for the device. I was
> impressed by its large safe operating
>  >area and 0.5J single pulse avalanche energy capability. Truly a
transistor
> that's hard to kill. (but not
>  >impossible)
>
>  >Robert
>
> Robert,
> If only I have killed many of them, usually from spikes in the gate, they
> are very susceptible to HV..
>
> Although the circuit is similar to the one I used, being 30+ I have
actually
> used the good old 2N3055, which is apparently much easier to kill, maybe
its
> my experience, but i've only killed a couple in that circuit, and most of
> them are from shorts whilst playing, not "in service". I do have a 4nF cap
> and a reverse diode across then though.
>
> Cheers
> Derek
>
>