The tranzorb limits the voltage by clamping. Your
circuit still remains powered. If there's too much
energy it will short circuit. Then the fuse protects
against fire.

It requires careful reading of spec sheets and some
testing to get the right combination, but then you
have something simple.

Does this application have a starter motor, do you
care about low voltage?

Cheers,
Bob

--- luis antonio prata barbosa
<luispratalistas@gmail.com> wrote:

> What waveform will I have ? I mean, when "load dump"
> happens will be the
> circuit cutted off ??? I need the circuit still
> working even during load
> dump time (400ms)...
> 
> 2007/5/23, Bob Blick <bbblick@sbcglobal.net>:
> >
> >
> > > The "Load Dump" fenomenum makes car voltage up
> to
> > > 80v or higher.
> > > The use of transorbs or proctection diodes
> require a
> > > series resistor that
> > > dissipates a lot of power and/or generates
> > > undesireable drop voltage.
> >
> > If you use a series polyswitch fuse and a big
> tranzorb
> > you can do pretty well.
> >
> > Cheerful regards,
> >
> > Bob

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