ulysses

Hi Ulysses

I just read a very informative post / reply of yours re 'Choosing a Power Transformer' and I'm hoping you can provide me with similar info PLEASE.

I have a 'power supply' with a duff transformer ('thermal fuse' in windings gone I suspect) so I am not able to check the Tx output voltage in order to buy a new one.

The power supply purpose is a charger for an 18v cordless drill and the output from the Charger is 21.5V at 1.4A, 30.1VA.

The charger has a bridge rectifier and smoothing and regulation etc circuitry and a relay (to cut off when fully charged I guess).

My question is this please ... what voltage inout should I be applying to the bridge rectifier in order to give the 21.5V output?

I understand PS theory (from years ago) but forgot more than I knew (smile) and your informative post reminded me, thanks!

Transformers ouptuts at 30 VA seem to leap from 18V to 24V so would 18V to the bridge be correct anyway or should I look for a Tx with higher voltage output.

Many Many Thanks
Flint
I live in the UK btw if you ever need a contact in UK.