MAKE A HIGH VOLTAGE SUPPLY IN 5 MINUTES

Step 2 Some Info about Flyback Transformers

Flyback transformers come in all different shapes and sizes. Pick a big one.

The challenge with the flyback transformer is to find 3 pins out of 10 to 20 pins. One pin will be the high voltage ground the other two pins will be that of the primary coil that will connect to the CFL's electronic board.

If you can get the schematic of the flyback transformer that will save you time. However you can figure out the pins by following the instructions here.

Danger - if you are going to get the flyback from a TV or CRT you need to discharge it. It can hold a dangerous charge even days after the TV or CRT is turned off (see picture for details).

Comments

[somebody12345]

This pin stuff is very confusing. could you explain it better???

[alien200049655]

Couldn't achieve the same effect from an "ignition coil" from a motorcycle or snowmobile? It seems to me that all you'd need to make it work is a 12VDC power source, and a way to simulate the effect of the ignition points (555 timer astable, half wave oscillator pulsing a 12V source to the points leads). Most ignition coils punch out 30,000 - 50,000 volts. I know the power you get from an ignition coil, because I'm a mechanic by trade.

[mohfaz]

as making this instructable I got several troubles: 1. I can't know which are iner wires or outer wires since the one pair of wire are on the one side and other are on the another!!! 2. to find the primary pins of the transformers i got 3 pins that they have 1 resistance !!!!

[Biotele]

get alligator clip wires and try different combination of hook ups between the circuit board and transformer. Make sure you have the power off when you are changing configuration. Also have the HV output close to ground so that it sparks when it works.

[jules15]

Dang that's smart hooking up the 9v batteries like that. Never would of thought of it

[brady911]

i ordered a new flyback on ebay and i was able to find the 0v pin, and i found a few pins from 1-4 ohms... so i used the 0.9 - 1.2 ohm pins... but when i went to do the Polarity test... i got a miniscule 1 - 2 volts DC. what am i doing wrong? does it always spike at 30 VDC

[brady911]

ok i found another set of pins that got a resistance of 1 - 0.8 ohms.. and i measurd a higher spike of 10 - 15 volts... i think i saw it spike at 40 once... so i got it now.

[insistent]

I cant find any pin that show 1 ohm, all of them are 0.

And what happen if i use a 10 volt RC car battery for step 1?

[Dirtie Hippie]

Can flyback transformers be shorted or bad? I followed the instructions in the linked page to find the pins. The 0 V pin was easy enough. But I get close to 1 ohm across several different pins, like six of them and in different configurations. So I used the two closest to 1 ohm pins and tested the polarity the way laid out on the page. I don't get any spikes in power any where near the mentioned 30 volts. The pins I think are the primary pins gave spikes but a pathetic 10 volt spike, when my input is 9 volts. And the polarity doesn't seem to matter. There was definitely some power conversion there because the am radio I was listening to in the background crackled when I was testing. I'm not sure how old the tv I got the transformer from was, 90's I think, 80's at the oldest. Is it possible that it's one of those AC transformers? Could that be the issue? Also, I didn't have any good batteries laying around, but lots of varying wall transformers. So I used ones that had the voltages described on the webpage. That couldn't be it, could it?

[Biotele]

It does not matter if the transformer is AC. It is very probable that the transformer is shorted. It will oscillate (thus AM radio interference) but will not produce High voltage. It also could be that the circuit itself is not in a high power oscillating mode because of improper matching in feedback. I solved this problem by placing a capacitor in the circuit. I explain this in step 4. I recommend when testing the circuit to have the outputs of the high voltage close to each other, in order to detect any circuit operation.

[Dirtie Hippie]

No, scratch what I said about identifying pins correctly. I must have made a mistake in the pin configuration. Because upon re-checking the voltage I get a volt drop from 9 volts to 6. What am I doing wrong? :(

[knoxarama]

i got a rather large 2kv flyback froma microwave, would that work? also, i only have six wires on mine, since two are ground and four are leads. it also doesn't have a cover.

[Kirbsome!]

From a microwave? Then its not a flyback, it's a MOT (microwave oven transformer). They plug in directly to mains.

[knoxarama]

woops. well, now i actually have a flyback from a crt. so yay.

[jakedeathless]

Just so everyone knows...in the name of safety, the capacitors( those big can-looking things) are what hold the dangerous charge ( enough to throw you across the room...if not kill you) and they can hold this charge for months even. So before touching anything in there, short the capacitor leads with an insulated screwdriver.

[Rishnai]

Good advice. I took apart an old computer monitor today that I know for a fact hadn't been plugged in for at least five years. Most of the capacitors were drained, but a couple of the really big ones still discharged some when I shorted them with my screwdriver, just to be safe. I bet folks thought I was setting off fireworks, that's how loud some of the discharges were. But yeah, five years.

[knoxarama]

i know i guy who did that with a kitchen knife and it ended up as a black twisted piece of metal.

[redstarsrbija]

ya, my uncle used fix tvs and monitors and one zapped him from one hand to the other(across the chest) and he landed on top of a desk across the room..... scary stuff

[knoxarama]

my cousins friends uncle did that and died

[philgenius]

If you calculate the joules using this, as long as it is under 16 joules and it doesn't go across the heart (like shocking a single finger), it should be safe.

But discharge just in case.

[Biotele]

very good point.

[blablabla123]

Can the flyback transformers get damaged easily? that is, through incorrect lead placement or incorrect polarity of input? Also, does the flyback transformer carry or sustain a current (like a capacitor) only after being used in a CRT monitor or not? to be more specific, after using a fully disconnected flyback transformer, is current stored as well, is there an electro-static surprise in for me if I unintentionally touch the flyback after use and power disconnected? thanks- great instructable by the way :D moaaaaar! :] -thanks

[bb908]

For my flyback transformer, i have found several different pins from which i can get a resistance of about 1 ohm. does it matter which one i connect it to?

[bb908]

and now i cant find it with either of my flybacks, and the multitester works fine

[bb908]

actually, i cant find a one ohm. the before mentioned were actually no ohms

[Biotele]

The no ohms pins are better candidates than the one ohm pins. Use alligator clips hooked to the cfl board to test the pins. The pin pair that gives the biggest spark are that of the primary. Keep the high voltage output close to its ground wire to observe that the circuit works when you are testing the pins.

[ne171pro]

When testing the CFL to find what pins are the "outer pins" Where is the power coming from?

[i_build_stuff]

i just took the board out of a large CRT television very very carefully it had been unplugged for only a day or so. The board i got is riddled with large capacitors and I'm to scared to touch anything let alone try to discharge it. On the biggest one it says on the side 200v 820uf 5258(m) can anyone tell me exactly how dangerous this thing is? Until l get a better understanding of this thing I'm puttin it in a box and stashin it.

[Biotele]

it can give you a jolt. Take a screwdriver with a rubber handle. Hold the screwdriver by the rubber handle and try to short the cap by touching both pins with the metal part of the screwdriver. You might get a loud bang (or maybe nothing if it is discharged). Keep one hand in your pocket. Do this to all the big caps.

[Metiz]

I have a flyback here that by eye looks exactly like the one you have used - same pin layout etc. is it save to asume that my pins are the same as yours?

[Biotele]

most flyback look alike. I doubt they are the same. It is better to test the pins.

[usualpyro95]

it may be that im a bit distracted, but where is the ground wire connected to the fbc coming from?

[Biotele]

One of the pins at the bottom of a flyback transformer is a ground pin for the high voltage outpur. In step 2 there is a link to a website that explains how to find it.

[elimist]

You think making one more, and connecting the HV of one to the zero volt of the other would work. Or would putting them in series overload them?

[Biotele]

Sorry, I didn't read your question carefully. The answer is yes, you can model the output of the flyback like a HV DC battery, and batteries can be put in series. That will augment your voltage.