Electric bug zapper

[Derek Fountain]

I had one of those bug zapper things that looks like a mini tennis
racket only with a wire mesh. It ran on a 9v battery and was
exceptionally effective. Sadly I made the mistake of taking it to
Australia where it got spotted by customs and confiscated.

Back in the UK I found another one, only this one is powered by 2 AA
batteries and and is nowhere near as effective. It takes several
contacts to kill a stubbon mossie, and hitting a wasp with it is a game
unto itself - will the stunned and angry wasp sting you before you've
had chance to whack it a few more times?

Anyway...

I could try to find another 9v one, but they're harder to get hold of
these days. Or I could find out how they work, what the electronics
inside looks like and maybe make a new 9v unit to go inside the one I
have. I choose the latter route. I know the very basics of electronics,
but no more.

I've googled for information on how bug zappers work and can only find
the obvious: the voltage is increased to a level where it'll stun or
kill an insect that touches the mesh. But I'd like more detail. Does
anyone have any resources they can point me to that explain how these
things get such a high voltage and how the voltage is deployed such that
is delivers a stunning shock?

 

[Anthony Fremont]

Derek Fountain wrote:

I've googled for information on how bug zappers work and can only find
the obvious: the voltage is increased to a level where it'll stun or
kill an insect that touches the mesh. But I'd like more detail. Does
anyone have any resources they can point me to that explain how these
things get such a high voltage and how the voltage is deployed such
that is delivers a stunning shock?

I would imagine that most are simple oscillators driving a diode/capacitor
voltage multiplier ladder. You should just be able to increase the input
voltage and obtain an increased output voltage. At some point, the stuff
will start arcing over so you likely won't be able to just use a 9V battery
in place of the 3V supply. OTOH, it may work perfectly so give it a try.

Be sorta careful though, you're talking about many hundreds or even
thousands of volts here. You'd probably have to try really hard before you
could kill yourself with it, but you could sure shock the piss out of
yourself. ;-)

 

[Jonathan Kirwan]

I had one of those bug zapper things that looks like a mini tennis
racket only with a wire mesh. It ran on a 9v battery and was
exceptionally effective. Sadly I made the mistake of taking it to
Australia where it got spotted by customs and confiscated.

Back in the UK I found another one, only this one is powered by 2 AA
batteries and and is nowhere near as effective. It takes several
contacts to kill a stubbon mossie, and hitting a wasp with it is a game
unto itself - will the stunned and angry wasp sting you before you've
had chance to whack it a few more times?

Anyway...

I could try to find another 9v one, but they're harder to get hold of
these days. Or I could find out how they work, what the electronics
inside looks like and maybe make a new 9v unit to go inside the one I
have. I choose the latter route. I know the very basics of electronics,
but no more.

I've googled for information on how bug zappers work and can only find
the obvious: the voltage is increased to a level where it'll stun or
kill an insect that touches the mesh. But I'd like more detail. Does
anyone have any resources they can point me to that explain how these
things get such a high voltage and how the voltage is deployed such that
is delivers a stunning shock?

Here's one using two D cells. Might be better:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40122

US$2 each, though shipping would put a kink in that.

As far as the circuits go, I think they look quite a bit like a camera
flash lamp circuit. At least, for the HV generation (not the lamp
part which will include a trigger transformer, lamp, and a thyristor
most likely.) Except that the transformer is likely arranged for
somewhat higher voltages at the outset. (300-400V for flash lamp, my
guess is 4kV or so for a bug zapper.) Probaby a BJT, a specially
wound transformer, a capacitor, a resistor or two. Not much.

Jon