Simple High Voltage Flyback inverter [without feedback coil]

Step 5 The primary coil

If you have made your own primary coil, skip this step.

Ways to find the primary coil:


Use the same method as in step 3, but now testing it on every pin, except for the 0V HV and +HV connections because we already found those.
(Warning: when applying voltage the primary coil, you will get a short high voltage pulse on the secondary coil, so don't touch it!, however it won't kill you)

OR

Use an Ohm meter:
- Measure the resistance between every pin (Ohms)
- When you find a coil with less than 1 ohm resistance, that's the primary.

OR

use the beep-test function from your multi-meter:
- Try every pin
- when you hear a beep, you found a coil :)


The polarity

The polarity of the primary coil seems to be hard to find at this moment.
I will try to find a method for it, but for now, you'll have to guess.

There will be only one working polarity, the other one will give no result, because then the gate of the MOSFET won't be switched.

Comments

[geckomage]

On most semi-modern flyback transformers there is a built in diode on the primary, as well as a rectifier on the secondary (helps smooth out the voltage). So the polatiry does matter (as you have said). One method i found to work well for finding the primary coil's polarity is this. After finding the pins for the primary, solder a few wires onto the pins (does not have to be permanent). Next, take your voltmeter and hook the positive probe (the red one) to the HV output wire (the big thick usually red wire on the top of the flyback) (this can be done with alligator clip probes or by using alligator clips on your probe tips. if no alligator clips are available just use some electrical tape to hold them on or something) then take your negative (black) probe and hook it to the HV 0v pin which you have already found. If your volt meter is like mine and automatically adjusts itself to measure the proper voltage, you should be fine. if not, i have never had this create more than a readable 35 volt spike. Then take your 9v battery and hold one of the connections on one of the terminals of the battery, then take the other and rapidly tap it with your finger (or something else if you dont want to risk shocking yourself, but i had no issues with this) to simulate pulsing DC current. Keep a watchful eye on your volt meter. (if its hooked up the wrong way you will get next to no voltage) then try flipping the polarity of the 9v battery. which ever one gives you a larger voltage spike is the correct polarity of the coil! enjoy :)

[Electorials]

That is indeed a good way for finding it ;)

[geckomage]

lol just thought i'd help anyone that needed it :D then you can see fairly easily which way it is (i dont know if you get arcs when you hook it up backwards) but ive always believed in starting with smaller voltages first ;D