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Reusing a Ballast Transformer

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Advanced Member level 4
Dec 2, 2010
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I have a busted 40w Electronics ballast , one used for 4 feet fl.. tube light.

The question is - is the transformer used in the circuit is rated 40+watt ?

so that I can alter it, rewind it, to use in a 40w smps circuit, offline.. 12v .. 3 amp etc.

Forget 12v 3amp... planning to use in a 5v , 1amp , is it okay ?

It doesn't works like that!! The trafo inside a ballast circuit, maybe a newer smps based flicker free or legacy LC ballasts, are used as inductors. But can you show where you found that trafo from? There are lots of different ballast designs available..

I have attached file using image menu, but cant see anything after finished.

Also added using attachment menu.. still nothing seen.

Did i miss something?

- - - Updated - - -

OK.. i think i have attached it now.
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The circuit seems to be of a flicker free ballast with possibly 1300x series transistor. But in these fluorescent lamp circuit, these ferrite cores are inductors. Some call it a "choke inductor". It might have 4 or more pins below, but there's only one wire wound all over the core. Rest of the pins are either left unused, or might be fused with its neighbor pin. There's no secondary wiring in it.

But you can use the ferrite core to design your own trafo, depending on its size, requirement and operating frequency.

Note: Ballasts are not power adapters, like the one in laptop. They just convert low frequency input (50Hz) to high frequency output (30kHz to 50kHz) for efficiency, and is specially designed for fluorescent lamps. ;-)

So if I completely rewind it, I can use it for say 5v, 1amp etc, at 50khz. worth a try?

So if I completely rewind it, I can use it for say 5v, 1amp etc, at 50khz. worth a try?
In a suitable SMPS circuit, yes. It would have little in common with the CFL inverter.

You have to design the SMPS circuit, e.g. using an switcher IC from or separate switch mode controller and MOSFET. Why not get you a ready-made SMPS transformer for the intended output range?

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