[Amps] Bias Zener Diodes In Parallel ?++

[alex]

Perhaps somebody should explain what SOA (Safe Operating Area) and what
"derating" is :)
Alex





> -----Original Message-----
> From: amps-admin@contesting.com [mailto:amps-admin@contesting.com]On
> Behalf Of Richard
> Sent: Tuesday, July 16, 2002 2:20 PM
> To: Douglas R Snowden; AMPS
> Subject: Re: [Amps] Bias Zener Diodes In Parallel ?
>
>
>
>
> >I have an amp that I have put several 5.6Volt @ 5watt zeners
> >in series for cathode bias.  They get way too hot with
> >about 800ma of current.  Can I parallel zeners to divide the
> >current without problems with balance between them?
> >
> Not without potential grief.  A more rugged and less costly cathode bias
> configuration is a series string of fwd-biased Si diodes.   Each diode =
> 0.7v.  // Also, the dissipation rating for zeners is @ 25ºC case temp.,
> which is highly unlikely without water cooling.  For use in the real
> world, divide the diss. rating by 3.  Thus, a "5w" /DO-5 case zener is ok
> with c. 1.6w.  A 5.6V, "5w" zener is good for c. 0.28A, but not 0.892A.
>
> cheers, Doug, N4IJ
> >
> >
> >
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>
>
> -  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
> www.vcnet.com/measures.
> end
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