[SOLVED] Cant use weird transformer

[addisonElliott]

Hello everyone, this is my first time being here. I am interested in electronics and I have a little bit of experience. I have one friend whom I can ask questions to and he usually is not online so I figured I need some more electronic friends to help answer simple questions of mine! I am wanting to make a very small PCB board to convert 120VAC to 12VDC. It actually is a very easy circuit and I have the bridge rectifiers and the voltage regulators required to do it. The biggest issue seems to be the transformers just to convert it down to 12VAC. I suppose it should be a bit more than 12VAC to compensate for the bridge rectifier and voltage regulator. Anyways, I had an old power inverter that I took apart and saw plenty of transformers in there. I thought these would be perfect, but the issue is I don't know how they hook up.

Here is an image of both sides of it.




There is two windings from one I can tell. One on each side of the transformer. They both read about 0.8ohms resistance. It even reads 0.8ohms resistance no matter what two pins you put it on, on the one side with multiple pins. Whenever I try to put 120VAC on it, it blows the circuit breaker. I have tried this with both sides and the same thing has happened.

Is there something I am missing?

 

[ark5230]

True these transformers are of different type, they are ferrite core and are used at higher frequencies than the AC mains.
The resistance measurement you carried out must be with a simple multimeter, if it shows 0.8 Ohms, you may check if the meter shows 0.00 for no resistance (with the two leads of multimeter joined together).
In fact the windings are very low resistance with fewer turns of relatively thick copper wire.
These are used in switch mode power supplies. Better you buy one mains transformer with output of about 15-18 volts AC (even 12V will do as the filtered output will be 1.4 x 12 = 16.8V) that will serve the purpose. If you are going to use it for some purpose, the current requirements will also have to be considered before procuring the transformer.

 

[addisonElliott]

Thank you, that's exactly what I needed to know.