Center-Tapped Transformers

Hi,

If I have a transformer with ratio of 1:2, and the transformer in center-tapped, does this ratio apply to the whole secondary winding, or between the two windings?

So just say I have an input of 12V, would I see 24V across the entire secondary winding (so 12 V in between each of the two), or would I see 48V across the entire secondary winding (24V in between each).

My guess is that you would see 24V across the entire secondary winding, but my coworker disagrees. He thinks it's a matter of convention, and that 1:2 can mean either of the two depending on how you interpret it.

Pretend the center tap does not exist, then do your conversion. 1:2 = 12V in, 24V out. The center tap is simply a feature, whether it's used or not.

If one buys a transformer with a 12VCT secondary, that means a 12V secondary which also happens to sport a tap in the middle (thus giving two 6V halves)...