[sci.electronics] Bug-Zapper

jph@ihlpe.ATT.COM (452is-Hayes) (07/12/88)

How can you make a homemade electric/electronic bug-zapper?  Looking
for something fairly uncomplicated.  Can it be something as simple as sections 
of a grid each hooked to the 2 different plates of a sizeable electrolytic 
charged sufficiently so that when a bug bridges the grid it gets
zapped by the cap's discharge thru its body and then re-charges? 
Or is there more to it than that?

J. Hayes, ihlpe!jph

hermann@calgary.UUCP (Michael Hermann) (07/13/88)

In article <3118@ihlpe.ATT.COM>, jph@ihlpe.ATT.COM (452is-Hayes) writes:
> How can you make a homemade electric/electronic bug-zapper?  Looking
> for something fairly uncomplicated.  Can it be something as simple as sections 
> of a grid each hooked to the 2 different plates of a sizeable electrolytic 
> charged sufficiently so that when a bug bridges the grid it gets
> zapped by the cap's discharge thru its body and then re-charges? 
> Or is there more to it than that?
> 
> J. Hayes, ihlpe!jph

This might work, but not too well I suspect. Figure a small fly or large 
misquito is at least 5 mm in all dimensions, go for a gap about 5 mm between
two _sturdy_ metal grills. How much potential do you need to realiably
(strong spark) bridge a sspark plug gap? ~15KV for a gap of 2-3 mm. Can be less
or the distance can be farther to get a good spark for bug killing.
    Suggestion: use the flyback transformer in an old TV, which have around 
15KV in output. Warning: _extremely_ dangerous to fool around with these, they
_will_ kill you if you're not careful. 
    Anyway, fairly simple, and certainly cheap.

-- 
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dale@amc-vlsi.UUCP (Dale Wlasitz) (07/13/88)

In article <3118@ihlpe.ATT.COM>, jph@ihlpe.ATT.COM (452is-Hayes) writes:
>> How can you make a homemade electric/electronic bug-zapper?  Looking
>> for something fairly uncomplicated. ...........
>> J. Hayes, ihlpe!jph

>    Suggestion: use the flyback transformer in an old TV, which have around
>15KV in output. Warning: _extremely_ dangerous to fool around with
>these, they
>_will_ kill you if you're not careful.
>    Anyway, fairly simple, and certainly cheap.
>
>--
>/------------------\  ARPA  calgary!hermann@cs.ubc.ca
>|   Mike Hermann   |  UUCP  ...uunet!alberta!calgary!hermann
>\------------------/  EAN   hermann@cpsc.calgary.c

	Ideally what you want to construct is a grid with high
potential, once the bug enters the "zap-zone" and the spark zaps
it the potential drops off therefore it is ideal to have
a current limiting output on the transformer ... say under 20 mA. I'm
sure only 4-5 mA should be sufficient to do in even the big ones.

	This current is lethal! If you play with this stuff be
careful, also install it so that no children (or adults, animals etc.)
can become zapped. I think a neon transformer would work, they
are around 30 KV and current limited as well? Cheap too, should be
surplus houses that have them. Anyone ever use one?

Dale

jimc@iscuva.ISCS.COM (Jim Cathey) (07/14/88)

In article <3118@ihlpe.ATT.COM>, jph@ihlpe.ATT.COM (452is-Hayes) writes:
> How can you make a homemade electric/electronic bug-zapper?  Looking
> for something fairly uncomplicated.  Can it be something as simple as sections 
> of a grid each hooked to the 2 different plates of a sizeable electrolytic 
> charged sufficiently so that when a bug bridges the grid it gets
> zapped by the cap's discharge thru its body and then re-charges? 
> Or is there more to it than that?

I suspect that that wouldn't work for more than the first bug.  I think
the commercial units use a heavy-duty step-up transformer to provide a
lot of power to the grid (something like a neon light transformer or an
oil burner ignition transformer).  This is to burn away the dead bug's
body.  A lightweight capacitor probably won't store enough energy to
both kill the bug and burn it away if it should stick.  For sure the
trickle charger you were talking about couldn't burn the bug off.  By
the way I don't think you can get an electrolytic cap that would be
suitable.  A better bet would be a HV capacitor charged to an extremely
high voltage.  I've seen some Leyden jar demos using a Van de Graff
generator for charging that would do a nice number on a bug!

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till@didsgn.UUCP (didsgn) (07/15/88)

ignition coils from motorcycles or cars will do a nice job as high 
voltage sources