Mini-power transformer ?

Thread Starter

Externet

Joined Nov 29, 2005
2,232
Hello.
Guts of 1A USB charger from AC have a minuscule transformer. Where to source such ? Part number ? The adapter accepts "100 to 240VAC" How can such tiny thing work on a quarter kilovolt ?
Re-purposing / canibalizing an adapter just like this, found it is for real, has about a cubic centimetre transformer. Is there any trick to achieve its performance/isolation ?
1713715281267.png
 

nsaspook

Joined Aug 27, 2009
13,418
Hello.
Guts of 1A USB charger from AC have a minuscule transformer. Where to source such ? Part number ? The adapter accepts "100 to 240VAC" How can such tiny thing work on a quarter kilovolt ?
Re-purposing / canibalizing an adapter just like this, found it is for real, has about a cubic centimetre transformer. Is there any trick to achieve its performance/isolation ?
View attachment 320416
The "100 to 240VAC" AC is rectified to DC. The small transformer is a high frequency switching supply type as per the link provided by @Ian0
 

MisterBill2

Joined Jan 23, 2018
18,943
The reason it can be so small is that it is operating at 100kHz or so.
The beauty of using a much higher frequency is that the transformers can be much smaller for a given power level. That is why the surplus avionics goodies all use 400 cycle or even 800 cycle transformers.
 
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