how to know the current of a transformer

Thread Starter

Ghina Bayyat

Joined Mar 11, 2018
i have a transformer 220v to 12v but i don't know how much current it can give . how can i know ? the only thing written on the transformer is the voltage


Joined Jul 18, 2013
I would put that at around 150va - 250va, see how that jives with the secondary voltage (gauge) at that Va.
Oops, that is in MM so that would be a little high, more like 75va.


Joined Oct 2, 2009
why sir ? what is it supposed to be ? maybe it isn't the original wire because it is an old transformer
4mm is almost #6 AWG. That is almost as fat as a pencil.
There is no way any winding or connecting wire will be 4mm which is capable of handling 35A. This is what I would see on my car battery connections.


Joined Oct 2, 2009
2mm is almost #12 AWG, good for 9A.

Don't measure the plastic insulation. Measure the enameled copper wire.
I am seeing 1mm = 18AWG, good for 2A.