Re: HV protection for receiver input?

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#2207

From: Harry Bloomfield
Date: Tue, 12 Aug 2003 10:12

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In article <0001HW.BB56508400106C52F0386600@news.individual.net>, dave-
usenet3016@mailblocks.com says...
 | I am trying to fix a car alarm/remote locking unit. It seems that punks are 
 | putting personal protection "zappers" to the bumpers of cars and frying the 
 | receiver input. 
 | 
 | The input is very simple: length of wire serves as antenna, connected to 
 | input of wide bandwidth transistor driving tuned circuit. 
 | 
 | Transistor is fried. How can I protect this from several thousand volts (I'm 
 | guessing here; what's the typical input from one of these zappers?)? Are 
 | air-gap devices recommended? 
 |

It sounds a little unlikely that the input could be damaged by putting 
a zapper to the car bumper, more likely the zapper is placed close to 
the actual antenna wire.

To protect this, you could connect the end of the wire to a small 
florescent tube, with the other end connected to ground. A neon warning 
lamp similarly connected, might also be worth trying.  

-- 
Regards,
         Harry (M1BYT)...

Remove the 'NOSPAM' in my email address to reply.

Free Amateur Radio Courses:-
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From: Harry Bloomfield <harry.m1bytNOSPAM@tiscali.co.uk>
Newsgroups: sci.electronics.design,alt.engineering.electrical,sci.electronics.repair,aus.electronics
Subject: Re: HV protection for receiver input?
Date: Tue, 12 Aug 2003 11:12:04 +0100
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