Re: HV protection for receiver input?

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#2200

From: Vermin
Date: Tue, 19 Aug 2003 08:24

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On Sun, 17 Aug 2003 01:20:50 GMT, Active8
<mcolasono@earthlink.net.invalid> wrote:

>In article <if7hjvgt4aaguuoghj5n088m707uls7m52@4ax.com>, 
>void@nowhere.com says...
>> On Sun, 10 Aug 2003 16:22:48 +0100, Paul Burridge
>> <redscar@waitrose.notformail.com> wrote:
>> 
>> >On 10 Aug 2003 09:41:48 -0400, Sam Goldwasser <sam@saul.cis.upenn.edu>
>> >wrote:
>> >
>> >>And the inductor is used how?  In series it will block the RF.  In parallel,
>> >>it will still look like a high impedance for the fast rise time spike of
>> >>a zap.
>> >
>> >Good point, Sam. So what's the definitive answer?
>> 
>> 1.5KE30CA (1500W 30V bidirectional Tranzorb). 
>> Couple of bucks each.
>> General Semiconductor.
>> 
>thanks. i've been thinking tranzorbs while reading all this and didn't 
>know who made 'em.
>
>but those stun guns generate about 20kV. is the 30V spec above the 
>voltage they turn on at?
>
>br,
>mike

No. 

That's the point. 

The transorb will clamp the 20KV to about 30V (actual clamp voltage
depends upon the pulse rise time) protecting your circuit.

They have very low capacitance (10 to 15pF) and so should not affect
your RF.

Another option is a GDT (gas discharge tube), even lower capacitance
(only a couple of pF) and can be purchased in as low as 90V DC
clamping voltages.

See: 

http://www.search.epcos.com/pls/prins/para_search.init?M_SPRACHID=2&M_PRFA=6&M_PGRP=PG_SA_2E

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From: Vermin <void@nowhere.com>
Newsgroups: sci.electronics.design,alt.engineering.electrical,sci.electronics.repair,aus.electronics
Subject: Re: HV protection for receiver input?
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