[Elecraft] Transformers

[Tom W8JI]

>I just bought a transformer, primary and secondary both spec'd at 120v. My 
>line voltage is
> 119.5 -- the secondary voltage is -- get ready -- 148v! The only thing I 
> can think of is
> that this is supposed to be the voltage under load. But I didn't think 
> that transformers
> were spec'd that way, normally.

Transformers are commonly spec'ed under full rated load current, much less 
often under no load conditions. After all, people generally want to know the 
voltage under operating load.

Because of ESR losses in small cheap transformers, it would not be unusual 
to find a noticeable step-up ratio to the secondary. To confirm that, turn 
it around and excite the secondary and measure the primary.

73 Tom