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United States - Member - Donald here, Campbell Lighting Co. Engineering Fields - Retired Engineers / Mentors - New Member

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Bug Lights

08/11/2008 9:59 PM

Does anyone know the specs on the small, inexpensive transformers used to create the high voltage spark needed to kill bugs, in a traditional Bug Zapper?? I tied to measure that outgoing voltage, but it was OFF the chart with a standard volt meter.

We have 120v incoming, (powering a small lighting ballast), and the zapper transformer..

Any help would be greatly appreciated.

Donald

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Anonymous Poster
#1

Re: Bug Lights

08/12/2008 8:14 AM

We do a lot of high voltage work, but never specifically on bug zappers.

Looking at the device, is output coming from a transformer and only that? Or is it a transformer connected to a "little black box" which then has an output lead to the zapper grid? And can you describe the shape of the transformer?

Anyway, I suspect the final voltage of your zapper is somewhere around 1000V - 2000V which is why your standard voltmeter couldn't handle it. If you want to measure it, one option is to get a high-voltage DMM probe sold through outlets like Digi-Key, etc. These just divide down the voltage by some ratio to something your meter can handle. So 1000V might measure as 100V, etc. However...if the HV source is low-current the probe itself can load down the HV and give a lower reading than is really present. There are more expensive dedicated HV meters which won't do this.

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#2

Re: Bug Lights

08/12/2008 5:36 PM

for some reason i thought the thread title was BUD LIGHT... must be happy hour somewere?

I need a lil volt zap to wake up!

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#3

Re: Bug Lights

08/12/2008 11:16 PM

Have a look at this. It is the least expensive way I know of to create the HV needed in your bug zapper.

http://hyperphysics.phy-astr.gsu.edu/Hbase/electronic/voldoub.html

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#13
In reply to #3

Re: Bug Lights

08/13/2008 2:53 AM

None of these devices will come close to being able to produce the voltages in a bug-zapper...

RF_G

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#18
In reply to #13

Re: Bug Lights

08/13/2008 11:45 AM

I suggest you look at this site, buy one of these inexpensive units, open it up and take a look. I'm a man of few words. Regarding the voltage doubler, tripler and etc. link I provided in an earlier post, with that information, you should be able to unleash your creative mind and figure out how to achieve almost any voltage required by simply adding diode/capacitor stages.

http://www.bugzapfun.com/

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#21
In reply to #3

Re: Bug Lights

08/13/2008 12:54 PM

A good post, but to anyone building this may I suggest that you need to be fully aware of the danger of electrocution with such circuits.....

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#4

Re: Bug Lights

08/12/2008 11:26 PM

How big a spark will it produce? It takes of the order of 20kV/cm or 50kV/inch to ionize air at ordinary temperature and humidity. So if it will jump 0.1 inch, its around 5kV etc.

Use a well-insulated screwdriver to shorten the gap and test the arc! If you become part of the circuit, you will know it, but it's not likely to be lethal unless you already had a significant heart problem before doing the testing...

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Anonymous Poster
#5

Re: Bug Lights

08/12/2008 11:29 PM

I am a welder but it seems to me you can do it with a ohm meter and ohms law. measure the input side of the transformer and that you know is at a constant 120 then measure the output side of the transformer. Then do the simple math, and remember E over I times R and P=EXI do you get it if not give me the two measurements and I think i can do it in my head if not there are plenty of fellows who do things like this for a living. I would not be surprised if an old oil burner transformer would do it. Good luck

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#6
In reply to #5

Re: Bug Lights

08/12/2008 11:55 PM

Thanks Guys, these are all great comments, I really do appreciate it..

donald

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#20
In reply to #5

Re: Bug Lights

08/13/2008 12:38 PM

No good doing that unless the wire is the same diameter, even then the ratio will vary with frequency. Many variables.

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#7

Re: Bug Lights

08/12/2008 11:57 PM

Hi. This is the way I measure voltage higher than my 1000 v meter measures. Connect 5 or six 1 meg ohm resisters in series. connect them across the high voltage source and turn the AC on. Very cautiously, measure the voltage across only one. Multiply this voltage times the number of resistors. This method also works for DC.

John SE Texas

ps. Transformers from discarded microwave ovens have high voltage.

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#10
In reply to #7

Re: Bug Lights

08/13/2008 12:57 AM

'ps. Transformers from discarded microwave ovens have high voltage.' True, but bug zappers have limited current capabilities, whereas the transformers from microwave ovens have definitely LETHAL current capability - don't get near them!

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#8

Re: Bug Lights

08/13/2008 12:04 AM

One procedure I have used in the past for this type of voltage determination is to apply a reduced ac voltage to the primary winding of the transformer. Then read the applied primary winding voltage and the resultant secondary winding voltage. The ratio of the (primary voltage)/(secondary voltage) is the ratio of your windings (turns of wire for primary vs secondary).

Take this and multiply your normal input voltage (presumably 120 volts) by the windings ratio and you have your normal operations output voltage.

For example if I apply 5 volts ac to the primary winding and get a reading of 100 volts at the secondary winding there are 20 turns on the secondary winding for each turn on the primary winding, i.e. the transformer steps up the voltage by a factor of 20. If under normal operations I run it with an input voltage (applied to the primary winding) of 120 volts ac then my secondary winding voltage would be 120v*20 or 2400 volts.

If you use this method I would suggest temporarily disconnecting the ballast for the lamps. I haven't figured out yet if it would screw up your readings although I suspect it would.

Good luck

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#9

Re: Bug Lights

08/13/2008 12:49 AM

just get 10 1meg resistors, wire them in series and connect it across the outputs you want to measure and then measure the voltage across any ONE resistor, put a zero on the end of the number you get and that's your devices output voltage

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#11

Re: Bug Lights

08/13/2008 1:01 AM

Depending on the model 4500 to 6000 volts

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Anonymous Poster
#12

Re: Bug Lights

08/13/2008 2:02 AM

Try a ballast from an old neon light. In my younger days I built a Jacob's ladder using one. Be careful - you could get quite a shock - possibly a fatal one.

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#14

Re: Bug Lights

08/13/2008 4:49 AM

Could this be relative of a u/v or ozone generator ?? I would like to make one of these.

Could a bug zapper serve three functions - u/v & visible light to attract the bubs, a zapper to kill them and an air purifier (ozonator).

Following on something I once read I loaned a quartz u/v lamp from my lab to a friend who had a son with chronic asthma. It worked well & he slept well when it was running. I expect the ozone generated killed off the sensitisers causing the asthma.

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#15

Re: Bug Lights

08/13/2008 9:18 AM

Most of the suggestions are good but, why not just disassemble it and look at the nameplate on the transformer and (while it is open) examine the other circuit components?

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#16

Re: Bug Lights

08/13/2008 10:01 AM

It depends on the distance between the electrodes, just like a automotive sparkplug. In normal atmospheric conditions, the general rule of thumb is 1,000 volts per mm. If the distance between the electrodes is .5" and the bug is .125 wide or long, then it would take 96,000 volts. This also can vary depending on the conductiveness of the object. The breakdown voltage can also be lowered if an high frequency AC is used.

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#17
In reply to #16

Re: Bug Lights

08/13/2008 10:34 AM

Check your math!

Using your value of 1,000V/mm, 0.5" = 12.7mm, so requires 12,700V. The 0.125" bug part reduces the gap to 0.375" = 9.5mm, requiring 9.5kV.

The unit must not spark in the absence of bugs, so 10kV would be about right, based on the 1kV/mm.

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#19

Re: Bug Lights

08/13/2008 11:53 AM

Campbell,

A wide range of voltages will work, the current limit will be the tricky part. You will want enough current to zap the bugs without starting fires, but you don't want such a low limit that a moth will occupy the thing for hours as it slowly cooks off.

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#22

Re: Bug Lights

08/13/2008 1:33 PM

Disconnect the transformer, put 120VAC on the secondary, and measure the voltage on the primary.

Transformer ratio (step up) = 120/measured voltage

Secondary voltage when 120V is connected to the primary = 120 x ratio

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#23
In reply to #22

Re: Bug Lights

08/13/2008 4:42 PM

What you recommended can be dangerous, the secondary winding make be of too low a resistance and allow too high a current to run, damaging it and you. Also, the isolation resistance may be too low for safety as well on the secondary, when used as a primary.

The insulation on the primary may also not be good enough at the new output voltage. Assuming it was a 120 to 12 volt transformer, you now have 1200 volts or close too, on a coil designed for 120 volts!!!

I believe it might be better to look for a small "step-up" transformer that is built for such jobs, or even the transformer from a strobe light may be good enough for the tiny currents needed to kill insects......with a suitable resistance inserted to keep currents down of course!!

Theoretically though you were right in what you said!!!

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#26
In reply to #23

Re: Bug Lights

08/13/2008 6:29 PM

The transformer in question, the one Donald is trying to get the specs on, is a step up transformer, so the test I suggested is not dangerous (assuming he knows how to work with 120VAC) and it will not damage the transformer.

After disconnecting the transformer from the bug light, connecting 120v to the secondary, and connecting a meter to the primary, there will be very little current flow through either winding because the meter has a high input impedance. Nothing else would be connected to the transformer so there is no possibility of drawing too much current through the transformer.

Concerning the insulation on the primary and secondary, when assuming a step down transformer you are correct. The test would put voltages on the primary and secondary that are much higher than the design voltages. (But then, there would be no reason to conduct this test on a step down). Since this is a step up transformer the test voltages are much lower than the design voltages on both the primary and secondary. For example: if the ratio is 10 with a 120v primary the secondary would normally be 1200v. during the test the secondary would be 120v and the primary would be 12v.

Rereading your post you may have assumed I was suggesting to use a step down as a step up. I was simply suggesting a way to get the specs on the existing bug light transformer. Then he would use that information to purchase similar transformers.

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Anonymous Poster
#24

Re: Bug Lights

08/13/2008 4:55 PM

I am surprized no one has suggested using an LCR meter to determine voltage ratios. The ratio of the inductance on one side to the inductance on the other side is the same as the turn ratios, thus the voltage ratios. No need to play with dangerous voltages.

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#25

Re: Bug Lights

08/13/2008 5:35 PM

Somebody else has said it, the voltage is ten thousand or upwards, i.e., at least that of an automotive spark coil or similar transformer, which being fed A.C. from the line with appropriate voltage drops, is supplying the neon light and the hot wire grid.

Some of the proposals here are dangerous.

I would suggest that anybody asking a question like this is not qualified to be screwing around the innards of one of these bug electrocution machines. Before anybody gets offended that assertion is demonstrably so by the large number of very simple proposals as to determining the voltage and, in an inverse manner, by some of the dangerous proposals.

What I don't understand is why not simply go out and buy a new bug zapper. After all they are all over the place for less than it would cost to carry out many of these ideas.

But, while I was wandering around looking to find out how they really do it (The answer is any number of ways), I came across this little "medical" idea. I offer it for amusement purposes only, and by "amusement" I mean just that. Don't try it.

http://www.vmgworldwide.com/zapper.htm

j.

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#27

Re: Bug Lights

08/13/2008 9:18 PM

I don't think bug zappers are really any good anyway. They actually attract insects that bite you on the way to the UV light. I also think that they kill indiscriminately, probably killing more beneficial insects than anything else.

And I don't think breathing vaporized bug guts, (or, worse yet, almost vaporized bug guts), is any good for you.

Maybe something like this is better:

http://www.usepropane.com/select/insect_control

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#28
In reply to #27

Re: Bug Lights

08/14/2008 5:59 AM

The Bug Zapper Lamps should only be used in a closed environment, outside is simply unfair on the environment as a whole.

Many old English houses used an even better method than burning propane or Bugzappers to drive of most of the unwanted (but not the wanted) insects. They placed a lavender bush at each corner of the house, so no matter from which way the breeze comes, the house still gets the smell of lavender (most humans will not detect it at this level for anyone who does not like the smell!). Bees love it though and it gives the local honey a far better taste I am told by bee keepers.....

Since we started following this practise about 4 years ago, we have had very few Mosquitoes in tzhe house or garden.

A few drops of Lavender oil on exposed skin areas certainly keeps European Mosquitoes at bay, we had a "proper test" in Italy this year with 6 people, 2 with Lavender oil and 4 without. The ones without Lavender oil changed their minds very, very rapidly and became also Mosquito free in a few minutes after applying it!!!

Whether it works on US (especially the striped ones in Florida) Mossies I cannot say, it would be great if someone there would make the test for us all!!

Use only very tiny amounts, its not like applying Sun Tan oil!!!!

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#29
In reply to #28

Re: Bug Lights

08/14/2008 11:50 PM

Thanks Guys for all you great answers!..

I am contracted out to these people who have a USA patent on a certain different type of bug zapper that is intended to be used with a very popular outdoor light fixture.

As we understand it, the Southern Coastline, especially around New Orleans is under siege with mosquitoes carrying the west nile virus, and many cases of encephalitis are being reported in that area, as well as Equine Encephalitis, which makes that area a prime customer of anything that kills mosquitoes..

One Power company said they would purchase 20,000 units as soon as they are ready.

So, it's tough work fighting all those people that think the lowly mosquito should be left alone to carry out that dirty work, but somebodys got to do it...... Might as well be me...

Donald

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#30
In reply to #29

Re: Bug Lights

08/15/2008 6:50 AM

There you really need something that ONLY kills mosquitoes and not the useful insects....quite a challenge!! Best wishes.

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#31
In reply to #30

Re: Bug Lights

08/15/2008 9:57 AM

An appropriate mesh on the outside would keep out larger insects, and significantly reduce the required frequency of cleaning.

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#32
In reply to #27

Re: Bug Lights

08/15/2008 3:52 PM

Ah, but no satisfying sound of sizzling when you actually GET your prey!!!

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