Homebrew PCBs

On Wed, 19 Nov 2003 03:06:24 -0000, Steve <alienrelics@...> wrote:

> Around here, a search of thrift stores turns up quite a few model
> train transformers and slot car tranformers, at very cheap prices.
>
> Not all light dimmers will handle a transformer as a load and may blow
> out. If the transformer is at too high a voltage, you can ease both
> problems by putting an incandescent light bulb in series with the
> primary and attach this to the light dimmer.
>
> Steve

I found out that variac transformers are really cheap at ebay.
while 100VA joke size costs 150eur at mailorder shops
the 1200VA variac i got for some 15 eur or so from ebay...

Please keep in mind that most variacs don't have a isolated output.
(So you may want to use a isolation transformer)
But normally you will use a stepdown transformer in any case to reduce
voltage and increase current. So this is not a problem.

Sure a variac doesn't substitute a regulated dc supply.
But for AC or rough rectified DC with loads of A is is just great. Also for 
repairs and so the variac with isolation transformer is very convenient.
(safer, no scope ground trouble, you can slowly increase the voltage while 
testing something).

It is also good for over-and undervoltage failure testing.

Not exactly on topic - but a good piece of equipment which should be 
recommended...

ST