Re: [TCML] I should have taken more electrical classes/MOSFET TC

[DC Cox <resonance@xxxxxxxxxxxx>]

MOSFETs work fine if you use the right ones.  Pushing the ratings as almost
everyone does will certainly destroy them.

Dr. Resonance




On Mon, Feb 23, 2009 at 12:22 PM, Weinhold Shannon L <
Shannon.L.Weinhold@xxxxxxxxxxxxxxx> wrote:

> Brother, I am in the same boat. Mosfets have proven to be an expensive
> waste of time. Good smoke bombs, that's what they are.
> Everybody says "yeah, you should use the power hexfets" and I'm like,
> "um, no thanks!"
> I have much better luck with power transistors. Give me a 250 watt
> resistor and a big heatsink and I can build something that works
> reliably. (and doubles as a backup heater in the winter time)
>
> To my ever reliable NTE29, I love thee.
> You were built for the undereducated mad scientist like me who refuses
> to take the time to understand things like VCE and ICEO.
> May you live long and continue absorbing the exhorberant amounts of
> current that I bestow on you forevermore.
>
> Good luck Scott.
> If you figure it out, let me know.
> :)
>
> Shannon Weinhold
> Klasdja Intelligent Innovations
>
> -----Original Message-----
> From: Scott Bogard [mailto:sdbogard@xxxxxxxxx]
> Sent: Sunday, February 22, 2009 5:58 PM
> To: Tesla Coil Mailing List
> Subject: [TCML] I should have taken more electrical classes/MOSFET TC
>
> Greetings all,
>     All right, I been doing a bit of reading and I need something
> cleared up in plain English.  A MOSFET is just like a vacuum tube
> triode, (minus the obvious things like a plate transformer and a
> vacuum) except a triode turns off with voltage, and a MOSFET turns on
> with voltage, is this correct?  A BJT turns on with current, and voltage
> has little to do with it, what turns on an IGBT?  Anyway concerning the
> MOSFETs and tubes, if the above assumption is correct, why are there not
> designs for MOSFET based coils that are similar to the Armstrong
> oscillator tube coils (for those who are looking for little arcs at very
> little cost (MOSFETs are cheap, tubes are pricey and require external
> circuitry.))  If I am understanding this correctly it should be
> relatively easy to design such a circuit as you should essentially just
> reverse the direction of the windings, and maybe hook it to the positive
> rail instead of the ground?  (Well relatively simple for those who have
> actually used MOSFETs without exploding them or burning them, MOSFETs
> and me do not get along, I don't know why, I never did anything to them
> (except blow them up, but that wasn't my fault was it?))  Anyway just
> looking for answers, perhaps I am totally misunderstanding how to use
> them properly, and an electronics course might have helped with that.
> Thanks for your patience!
>
> Scott Bogard.
>
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