Re: [Amps] Crowbar components

[R.Measures <r@somis.org>]

On Jul 21, 2004, at 8:47 AM, Frank Goenninger wrote:

> Hi all on the list:
>
> There have now been several posts here pointing
> to
>
> http://www.qsl.net/oe5jfl/flashover.htm
>
> as a suitable crowbar circuit. I want to copy that
> one...
>
> When searching for suitable components I could not
> find a suitable opto-coupled Diac as shown in the
> mains circuit.
>
> My HV transformer will draw abt. 21A of current so
> I need a Diac able to withstand that or I have to
> substitute that part with ??? A diac controlling
> a thyristor ? Or ??
>
> Are there any such diacs or what would a suitable
> replacement circuit not altering speed too much
> look like?

Frank --  Why go to the trouble of interrupting the flow of electric 
mains current by special means?  The stored charge in the filter-C is 
what can produce enough peak current to cause bent filaments in 3-500Zs 
or gold to sputter from the grid of 8877s, and this current is already 
limited by the glitch resistor -- provided it is able to withstand the 
Joules available from the filter-C without going kaput.
> Thx for your help!
>
> 73, Frank DG1SBG
>
>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org

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