Wonder what type of mini transformers these are and if they could be used for anything in Hifi alternatively.
Got it out of led lamp.
Nice 400v electrolytic to be found in and can be reused. And the other parts?
Who knows what can be done with it?
Got it out of led lamp.
Nice 400v electrolytic to be found in and can be reused. And the other parts?
Who knows what can be done with it?
Attachments
It is a high frequency transformer for the switching type supply that the PCB is.
It will run at many tens or even hundreds of kHz.
It will run at many tens or even hundreds of kHz.
It is probably an inductor, maybe with a tap, in the 1~10mH range.
As it can withstand some DC bias, it could be used in a CLC supply, for currents <100mA
As it can withstand some DC bias, it could be used in a CLC supply, for currents <100mA
I think @Elvee is correct. I can see the number on the chip (9938) which seems to be a buck convertor for LED's
https://pdf1.alldatasheet.com/datasheet-pdf/view/1140993/BPS/BP9938X.html
https://pdf1.alldatasheet.com/datasheet-pdf/view/1140993/BPS/BP9938X.html
These components are found in wall-wart power adaptors, as well. The cause of most frequent failure is the leaking big capacitor. I just replaced one.
Does anyone know if these mini transformers could be used as step up transformer for piezo tweeter?
Maybe two of them in parallel if there would be too much current for one?
Who knows how these little transformers have their windings made?
Maybe two of them in parallel if there would be too much current for one?
Who knows how these little transformers have their windings made?
The transformer adapts 10 to 20 times the voltage from 220 to 12 or 24 volts.
If these mini transformers are paralleled (same types) does it help the current carrying capacity?
Can the voltage relationship be somehow influenced ?
Would be nice to adapt it to piezo step up purposes.
If these mini transformers are paralleled (same types) does it help the current carrying capacity?
Can the voltage relationship be somehow influenced ?
Would be nice to adapt it to piezo step up purposes.
I suspect they would be less than ideal as they are optimised to work at frequencies typically above 50kHz. You would have to try one, load it with a typical capacitive load a piezo tweeter presents as and see how flat or otherwise the output is and also what sort of step up ratio you get.
The problem with these things is that if you can’t get them apart they are pretty well useless to you. Let’s see you get on 1000 turns of #40 by hand through that window. Their application didn’t even use the full winding window, so don’t expect high performance for the size as is. Since the size was limited by the electrolytics there wasn’t much point of using the smaller cores. It’s probably just an inductor, with the center leg gapped.
Cores and bobbins that size are cheap enough nowadays, and even Digikey has them.
And of course it’s the caps that go out. Service life at rated ripple currents are somewhere in between that of an incandescent light bulb and an old F40T12. I wonder if they will start making “long life” LED lamps with MKP’s.
Cores and bobbins that size are cheap enough nowadays, and even Digikey has them.
And of course it’s the caps that go out. Service life at rated ripple currents are somewhere in between that of an incandescent light bulb and an old F40T12. I wonder if they will start making “long life” LED lamps with MKP’s.
Friend uses MKP + bleed resistor + bridge - 4x 4007....for aviation tower lights.
Pretty reliable, no issues since many years.
Uses them in 12, 24 & 48V strings.
He is one of only two makers in India, makes them by the thousand in quantity.
That thing in above photos is an induction coil or choke, a single winding.
You need at least two to make a transformer...
And in mosquito racquets one winding is a feedback winding, to control the circuit.
Pretty reliable, no issues since many years.
Uses them in 12, 24 & 48V strings.
He is one of only two makers in India, makes them by the thousand in quantity.
That thing in above photos is an induction coil or choke, a single winding.
You need at least two to make a transformer...
And in mosquito racquets one winding is a feedback winding, to control the circuit.