Inside a bug zapper racket / racquet , with schematic.
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- Опубликовано: 15 май 2016
- These devices have been around for a while. They're basically a bat/racket/racquet that has an electrified grid that zaps bugs when they pass near it. The units tend to run from two AA cells and have a very simple step-up circuit involving an initial transformer stage and then a short multiplier to charge the main capacitor to a high voltage. When an insect makes contact with two layers of the grid the capacitor discharges through it.
Two things surprised me about this design. the location of the NPN transistor in the transformer circuit and the unusual two section rectifier/multiplier that charges the main capacitor. Particularly unusual is the choice of different capacitor values for the two lower stages of the multiplier. I would guess it might be to optimise efficiency or to keep the cost to the minimum.
The older bats used to have open rows of alternate polarity wires, but the newer ones use a sandwich of three meshes and insulating layers. I would guess it's actually a lot easier to make them this way, and also results in a slightly safer and stronger bat.
The boost circuit isn't really designed for continuous operation, although the switching transistor only reached a temperature of 50C in normal use.
If you enjoy this channel than you can help support it with a dollar for coffee, cookies and technically interesting insect obliterators at / bigclive
I actually have to thank you Clive. I have worked in electronics manufacturing doing low skill assembly work for over 8 years now and have never bothered to learn how electronics worked. Well I tried for like a couple weeks due to an ever present job scare, but then got caught up in other (lazier) habits and kind of stopped. When I came across your channel though, I felt comfortable looking at electronics because you are there to basically give a rough (sometimes thorough) and easily understandable explanation of the cheap gadgets you buy. This has revived my interest in electronics and now I consider it something of a hobby. My knowledge is still the most basic of the basic, but I am working on it with the help of your videos. Please give me your knowledge senpai ,but please be gentle.
We have similar versions in the U.S. and I rip the racquet off and mount contacts in the end and just plug them in when I need HV sources for plasma displays and general tinkering with. Also got tired of wee batteries going dead so I installed a fat 18650 rechargeable in the handle. Also installed a proper power switch so I could stop stunning myself. And thank you for doing such wonderful videos. Your efforts and warnings will likely save me, er... delay my eventual death by electrocution. If the isotopes don't do me in first. Good thing about being an old fart. Cancer has no teeth as a threat anymore.
I love how you measure caps in Picofarts now.
I've got several of these, some are better than others. It seems that the cheaper ones from discount stores are the more powerful ones, and they maintain they're charge for a long time. These are a real hoot to use on warm summer nights, you can really do a number on the no-see-ums and skeeters.
I took electronics two times in degree programs. The first time was at the end of the vacuum tube era with very few semi-conductors and the second after almost all the tubes had been replaced. Electron flow vs conventional current flow, in theory from a bunch of dusty professors that all had severe issues getting along with humans. I have been damaged by my experience, learning all the math and then learning it again exactly backwards. Because of my skills I normally was placed in the head of departments, maintenance, electrical and electronics but not confined to the areas. I was always doing what I loved. It's snice to see another electricity/electronics person doing what they love.
The secondary circuit contains diode (connecting 100pF and 22nF) in the forward path while charging all 3 capacitors. This diode stops the current from the 2kV capacitor reaching the metal net during discharge, thus reducing a potential risk of nasty burns. The other 2 diodes are used for safe discharge of 100pF and 2.2nF through the 22MOhm resistors to avoid shock from the 2kV capacitor when the bat is not in use. At any given point the 22nF capacitor contains 2kV potential and charge (so be careful while disassembly), since it has no path to discharge.
I love these, they work very well. Especially with flys and mosquitos.
My mum had one of the bug zapper rackets with alternating rods back when I was still living with her.
I think the old style ones you mentioned simply solved the wiring headache of interleaved bars by simply using something approximate to two combs facing each other.
I've poked my fingers into nasty places on more than one occasion in the past
The person that cooked this up, should get the Nobel prize.
Thanks! I've been wondering how those things work for a while now. Great video!
Great idea for a teardown. Love the channel, keep up the good work BC!
Thanks for showing this. Bought one of these at the annual spring tent sale at the local hardware store. Haven't had a chance to try it out yet.
I've got one wired up to 4.5V continuous. It's slightly warm after running it for a few hours. It makes a louder snap than before with 3V from batteries.. I've got it positioned over a fruit fly trap to kill them all as they try to go in.
I've had one of these for years.....it is the best mossie killer I have ever had. Don't kill spiders
Love your videos...they are a critical part in a relaxing evening.
I have one of these, virtually identical in design, with subtle differences and dismantled it as I played this video. My pcb is slightly different, with only 1 large capacitor, same transistor and transformer. Your Poundland one looks better quality inside than mine which I inherited, so supplier unknown.They work great. Swatted an annoying fly at work and works great with wasps.
A friend of mine had one of the older ones with the horizontal grids and decided to tap me on the shoulder while I was doing some electrical work in his house. Once I recovered I moved all the switches around in his 4 gang switch box in his den. he goes to turn on his den lights and the bathroom lights come on.
Great video! This is the video that gained me as a new sub for you about three years ago. Well, I'm back here again this morning to ask you to please consider doing a "Part 2" to this zapper video, if you have the time, of course.