Introduction: How to Find the Primary and the Secondary Coils of a FlyBack Transformer
The main problem, in most cases, is that you don't know the pinout diagram of a flyback transformer. So, I shall try to give you a simple method to find the primary coil input pins and also the 0 V output pin of the HV secondary coil.
-=I do not take full credit for this=-
Step 1: How to Find the 0 V Pin Connection of the Secundary Coil?
With a common digital ohmeter it is impossible to find the secondary coil pinout because its resistance is much too high. The main HV output is simple to find : this is the big red cable with the suction cup, but you need to find the 0 V pin of the secondary coil on the flyback transformer. So, I give you a simple method to find this 0v pin :
a) You need a 24 V DC power supply and a digital voltmeter set in 20 V range. Connect the + input of your voltmeter to the THT ouput plug ( in the suction cup ) and the (-) to the 0V of your power supply. Then, with the +24V output from your power supply, test each pin of your flyback transformer. When you measure a voltage between 5 and 10 V you have found the 0 V pin of your secondary coil. This is very simple... Look at the diagram and the photo below :
Step 2: How to Find the Pins Location of the Primary Coil?
With a simple ohmeter this is very simple, you will find easily the primary inputs because the coil resistance is about 1 ohm
Step 3: How to Find the Polarity of the Primary Coil?
The purpose is to find the polarity of your primary coil. You need a simple 9 V battery. Connect a digital voltmeter set in 100 V range between the main THT output and the 0 V pin of the secondary that you have indentified in test #1. With the 9 V battery send a short pulse on the primary input, measure the spike of the voltage, then reverse the polarity of your 9 V battery. When you get the max voltage ( about a 30 V spike ) you have found the correct polarity of your primary coil. The (+) is the pin number 2 and the (-) is the pin number 1 in the main diagram.
31 Comments
11 years ago on Introduction
i don't have 24 volts dc power supply but i've 12 volts dc power supply
please give me a advice
Reply 11 years ago on Introduction
That might work, if it does then you should see around 3 volts on your meter.
Reply 8 years ago on Introduction
I can confirm that reading.
Reply 1 year ago
i got 0.6v from a 12v 2.5 power supply is that bad?
Question 1 year ago
All info in the picture!
-Exacly whitch pin / cable is the high voltage's 0V?
-Where i am supposed to connect the "in"-power?
-How many Volts?
...and whitch frequence should i give the input?
Thanks a lot!
2 years ago
Can you explain this scheme
Reply 2 years ago
HR 6060
10 years ago on Introduction
I'm trying to find the pins to the primary coil. I bought a new flyback a couple of weeks ago. My flyback has 10 pins. I got these results:
Pins ..... Resistance
1 + 5 .... 2 ohms
1 + 9 .... 1.8 ohms
5 + 9 .... 0.9 ohms
2 + 8 .... 0.9 ohms
3 + 4 .... 0.8 ohms
3 + 6 .... 0.8 ohms
4 + 6 .... 0.6 ohms
All the other combinations (i.e; pins 1 + 3) produced no resistance, so that means that pins 1 + 3 are not connected. Conversely, this means that pins 1+5+9 are connected; pins 2+8 are connected; pins 3+4+6 are connected; and pin 7 and pin 10 are not connected to any other pins.
The first problem is that many of these gave me a resistance close to 1 ohm, so I still don't know which pins to use for the primary coil.
The second problem is that a flyback should have two sets of connected pins; pins that connect to the primary coil, and pins the connect to the secondary coil. However, I seem to have 3 sets of connected pins (or five sets, depending on how you count). Does this mean something is disconnected inside my flyback?
I didn't know what to do, so I just went ahead and connected it to the CFL circuit. I tried pins 5+9, 2+8, and 3+4 as the pins to the primary coil, along with every combination of the 4 pins on the CFL circuit, but did not get a single arc for any of them. Does this mean that my brand-new flyback is bad?
Reply 2 years ago
The thing is some pins (3 pins which a have resistance value 1 pairs of the 3 pins have a resistance of more than 1 kilo ohm....that does NOT show contact or short) pins that a connected should have a resistance that is measured in ohm NOT kilo ohm. Basic electronics 101😂😂😂😂😂😂😂😂😂😂
Reply 10 years ago on Introduction
it might be bad double check with each set of pins and if it still does not work buy another flyback and see if it works
Reply 10 years ago on Introduction
Alrighty. Will do. Thanks!
Reply 10 years ago on Introduction
your welcome
12 years ago on Introduction
don't forget guys. ac from wall socket will not work. frequency is too low.
Reply 5 years ago
using a fluorescent ballast as a driver into the primary puts out some serious voltage. i would suggest submerging the whole thing in mineral oil so as to prevent any shorts before using it to create any really high voltage (10k - 50k volts)
Reply 5 years ago
you can even use a driver from a CFL. plenty of videos out there on youtube and such about it.
Reply 5 years ago
thanks for the late reply but i've learnt much more in the past six years. thanks anyway
11 years ago on Introduction
so i know what the main THT out put is but i have 3 other wires hanging about what are they 4
Reply 5 years ago
probably primary in and a ground. primary in is usually red and white ground is green or grey. i'm just going off the flybacks i salvaged from old crt monitors though.
7 years ago on Introduction
I am replacing the volt meter with led and also woks, led is on even only a small light ( I use red one for easy to look at)
8 years ago on Introduction
i tried to find primary and secondary for 4 different flybacks . First of all there are many combinations of pins which have resistance of around 1 ohm and for the secondary i got at most 0.6 volts with 18 volts supply.