This is the high voltage page. It contains information on my attempts to build tesla coils and other high voltage devices. At the moment as u can see there is not much here. That is because I have not managed to borrow a digital camera yet to take the pictures necessary for this page to much value. The following is just a taster for things to come.
This is by far my most successful high voltage device to date, and perhaps not coincidentally, the easiest to make. I got the idea for this from Greg, off of his page 'Greg's Garage' This is an excellent website for high voltage things, including tesla coil, and has some great pictures of the latter. I recommend anyone interested in high voltages to visit it and it can be found on my link page, or at Greg's Garage . In order to make this device you will need the following items;
The automotive ignition coil is the single most expensive component. New these cost about 16 pounds but if you are lucky enough to find one second hand they can cost as little as 2 pounds. The type u must get is an older type that actually contains coils of wire, not a newer electronic one. The old ones are cylindrical whereas the newer electronic ones are all sorts of weird shapes. Also it is better to get one that contains oil for extra insulation and one that does not contains a smoothing capacitor. This type is usually the cheapest to buy new as it contains the least components. If in doubt talk to the guy in the shop.
You might have some mains wire lying around. If not the best kind to buy is thickly insulated stuff that contains only one channel of wire/wires. I say channel, because it does not matter whether it is flex or single strand as long as there is only one of them. I bought mine from an electrical shop for around 80 pence a meter.
The dimmer swtich can be bought easily from any lighting shop for around 6-7 pounds. The greater the maximum wattage the better as it is less likely to blow. Also, if u can, buy a box to go on the back of the dimmer switch such as is used if a dimmer switch is too be mounted on a wall for normal use. This makes the circuit safer and neater and only costs about 80p
The capacitor can be bought in a car bits shop such as halfords, or better from somewhere like maplins. 3 microfarads is about right. The greater the capacitance the greater the end voltage of the system but also the more likely something is to explode and kill you, or to just explode and waste your money. Make sure the capacitor that you use is capable of withstanding 240 volts.
The circuit you should make with these components looks like this;
My circuit’s power comes from a mains wire that used to lead to an extension lead. I chopped this off at a length of 2 meters. Mains wire like this usually contains three different wires, a blue one, a brown one, and a yellow and green one. Brown is Live, blue is neutral (WARNING don't get this mixed up or u may die!), and green/yellow is earth. If u are unsure of ANY of this get help before attempting to build this circuit, or using mains in any home built circuit. Mains electricity can KILL you easily and quickly, although not without pain. The mains wire used in the circuit differs from that used in the extension lead power supply as it only has one wire inside it and has much thicker insulation. I bought the thickest insulated I could, just to make sure. As soon as I get hold of a digital camera I will post pictures of my setup. I placed the capacitor inside a plastic plumbing tube, such as I use for spud gun barrels, as it is not designed for use in a mains circuit and may fail/explode. Also, because the two contacts on the cap are the one wire coming out of it and the metal case, in order to insulate it I had to wrap it in thick layers of insulation tape and duct tape. This is not ideal for safety, yet another reason why I placed the entire capacitor inside a tube of plastic. Now the only contact with the capacitor I have are a wire going into the tube and another coming out the other end for connection with the mains circuit. The dimmer switch is designed for mains circuits so is safer. Also, I bought a box to go on the back of the dimmer switch, such as is used when using one properly for lighting to mount it on the wall. This cost me 80p
The live output terminal is the inside of the plastic funnel that extends out of the top of the ignition coil. The neutral terminal is the outside of the metal case. Of course if you have wired the ignition coil the wrong way round this may be reversed. Before plugging in the circuit to the mains place a long metal object into the plastic funnel so that it touches the metal at the funnels bottom. Now turn the dimmer switch all the way down and plug the circuit in. When you turn the dimmer switch on you will hopefully hear a buzzing noise. As you turn up the dimmer switch this buzzing should increase in amplitude. Turn the circuit off. Now, take a long insulated thing (30cm's is safe) such as a long piece of plastic or wood and attach a wire to one end. Attach the other end of the wire to the outside of the ignition coil. Now, with the dimmer switch turned all the way down, turn on the circuit. When you place the end of the wire attached to the outside of the coil against the live output you should see small sparks. When you turn the dimmer switch up these will increase in size. If this happens your circuit is working. Just be careful and don't get shocked!
The ignition coil is a step-up transformer. It has a turns ration of around 1:100, meaning if you put 240 volts in, you'd get around 24000 colts out. This is quite high. Unfortunately if you just connected an ignition coil to the mains the ignition coil would over heat and explode and the output would be of high enough current to kill you. The capacitor solves this as it provides capacitive resistance or reactance. This limits the current in the mains circuit. It can still kill you but the ignition coil will not over heat. The dimmer switch just enhances the overall performance but is not vital. It does this buy squashing the sine wave of normal a.c. This increases the rate of change of voltage of the mains current going into the ignition coil further increasing the voltage output. It also allows the output voltage to be lessened at the turning of the 'dimmer' which is in itself very useful.
The output is around 40,000 volts. This is very high and translates to around 1.3cm's of arc. This will of course be at 50 Hz which is mains frequency. This output will have a very low current; probably around 5 milliamps, but that is a guess. As a result touching this output will not kill you (probably), assuming of course that you have used the right capacitor. If you have used a different cap then it might well kill you either when you touch it or when the ignition coil explodes and shrapnel hits you and hot oil scalds your flesh. Either way make sure u have the right capacitor. I have touched this output (by accident :-) ) and it hurts a lot. It didn't kill me though. If you really want to see how much it hurts (which I don't recommend) then turn the dimmer switch all the way down first and slowly turn it up. Make sure you have used the right cap first or you may die straight away.