Hey, I am trying to make a variable power supply and found that transformers are hard to find in working order when salvaging them. I finally found one that I think will work but the circuit that it was in was complex and even seemed to rectify the signal before sending it through the primary winding which I thought was weird. The transformer seems to be purely the windings and I don't want to blow it up when I plug it into the wall. The battery charger it came from stepped the voltage down to about 5V and I think it might have been regulated but I need to check the parts to confirm this. If I could get a higher output that would be great and I don't need it to be regulated for the purposes I am going to use the power supply for. Is there a circuit I can use to get the transformer to work properly?
If true, it's probably from a "off-line switch mode power supply", in which case you can not connect it directly to mains AC voltage. Transformers/coupled inductors (if it was a flyback) of that type are meant to run at much higher frequencies.
Is there a way to rectify the signal then put it through the transformer and use a less complex circuit? I don't mind skipping on the switching feature if it won't hurt the transformer or circuit. All I really need is for the transformer to step down the voltage to a workable level but I don't want to burn something up in an effort to make it simple ether.
No you can't skimp on the switching feature which is required for the transformer to work. The switching regulator converts the DC to high frequency AC (30kHz to 300kHz) to power the transformer which will not work on low mains frequencies (50 to 60Hz). If you connect the transformer directly to the mains, a huge current will flow causing a fuse to blow.
Thanks everyone for the input. I guess I will need a different transformer for what I am trying to do. Until I find one that will work batteries are always a good substitute for a DC power power supply, but it is also nice to not have to replace them.
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