In article et, dave-
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)...

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