Hi there,
I need an answare.
I have a transformer. It's rating is 250V, 12-0-12V, 5Amp. So it has two possible power rating. It might be 12x5=60VA or 24x5=120VA. Which rating is correct?

 

I think that is with a 24 volt center-tapped secondary, so the VA rating would be 5A x 24V maximum = 120 VA. If your transformer has an E-I core and weighs near 2.55 pounds (1.2 kg for the "civilised world or about 1.5 kg for a toroid, then I would take that as confirmation.

 

I think that is with a 24 volt center-tapped secondary, so the VA rating would be 5A x 24V maximum = 120 VA. If your transformer has an E-I core and weighs near 2.55 pounds (1.2 kg for the "civilised world or about 1.5 kg for a toroid, then I would take that as confirmation.

yap! it is 24v with center-tapped. it is built with E-I core also. Dimension is 68x45x58 mm². i m not sure about weight. it may b arround 1kilo. here i upload a pic of it.

 

Then I guess we know what it is now.

 

any guess about it's va rating?

 

For its type of construction the weight is consistent with your calculation for 120 VA.

 

Ow... so, it is possibly a 120va transfomer. thank you for your kind help.