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How to use a transformer to step-up voltage Answered


I was wondering how to use a transformer to step-up volage. I got one of those shocker fly swatters and took it apart, and saw that it used a couple of transistors, capacitors, and the main thing, the small 5-pin transformer. How does it work? How can I increase the voltage? 


I see nobody answered your question.

I am going to assume you know about magnetic field theory.

A transformer creates a magnetic field in the primary coil and that creates a current in the secondary.

If you take a transformer core and wrap a wire around it ten times let’s call this the primary winding and then you wrap a second wire around the transformer core ten times let’s call this the secondary winding.

Then apply an alternating current to the primary winding and measure the output of the secondary.

So you put 10 volts in the primary and got 5 volts at the secondary you have a step down transformer of 50% efficacy.

Now let’s wrap the secondary 100 times and leave the primary at ten turns, then apply the same alternating current.

This time you get 50 volts on the secondary this is a step up transformer of 50% efficacy.

The 5 pin transformer you mentioned should have ether the primary or the secondary center taped.

Now this is just an example I haven’t seen your transformer.

It has three windings 1 will have a large number of turns the other two will have fewer turns but they are connected together so they can be more turns or fewer turns than the first winding.

You can’t tell by looking at it however you can tell by connecting an AC source to it and measuring the output of the other windings.

This is not always the case but usually the side with two wires is one winding and the side with three wires is the center tapped windings, you can confirm this with a multimeter and checking the continuity between the pins.

Does this help?

Yes this was very helpful! One question, do you have to apply an AC current? Cannot you use DC?


Transformers do not work with dc.

It needs to be AC or DC switched on and off at a frequency.

mark me as best answer.

I dont like google search for things like this eather they always run around what you want to know and tell you what you don't need.


Yes I know that is exactly my problem with google!
Oh, I have know idea how to mark it as the best answer. I featured it?

Thank you very much for you help!

This should work with your components

The diode on the secondary and the cap on the secondary can be from any flash camera or the taser fly swatter.

It is a taser circuit just about any general purpose NPN and PNP transistors will due.

High Voltage 2.gif

Ok, thank you very much! The secondary- very high uF? Like 2,000?

Didn't you say that you needed an AC current or a DC switched on and off at a frequency? I'm assuming the transistors would have something to do with that?

What's the copyright on this schematic? ( just curious :D)


Thank you Jesepf for all your help!

Hope to see another i'ble from you soon!

If a transformer has a 10:1 coil, it's usually used to drop 120v to 12v. In reverse, it would raise 12v to 120v, or 120v to 1200v (depending on insulation breakdown). Watts are conserved, so if a 120v to 12v is rated for 1 amp @ 12v (12watts), then it can only produce .1 amp at 120v (12watts).

Its a transformer, to start with, look up how transformers work. Then work out how to make the output voltage higher.....
They CAN pack a lethal punch.

"Then work out how to make the output voltage higher;" that's what I need help with!!!

Google searches on the topic are too vague. . .

then search on how to make Google searches on the topic that are too vague less vague.