Homebrew PCBs

Simon Gornall wrote:

> 
> Oh, I'll easily admit I don't fully understand everything I need to
> know for this :) Yet :)
> 
And i admit that didn't look to what CAT4101 were.

> > 
> My understanding was that you tend to vary either current or voltage
> in the pulses (so a constant-voltage, varying current supply would be
> ok). The CAT4101 has a wide range of voltage over which it will work
> (2-24v), so I'm covered, as long as a constant supply level at varying
> current is ok.

You need fixed voltage limited current that varies with board size. The
most important is respect current densities. 

> Ok - I'd seen 2x rather than 3x, but ok. I was aware it ought to be
> different, that was why there are 15 CAT4101's in the forward
> direction and 30 of them in the reverse direction. I wasn't actually
> planning on running them at max output, and the current ought to be a
> function of the board area anyway, right ?

My mistake, 10 to 20 for time relation, 3 or more for current. Just
checked. You wont need more psu power on reverse. Such sort pulse can be
helped with capacitors. But i should only speak about current not power
since voltage is still unknown to me...

> Right - I was planning on using the 5v supply on an ATX PSU and see
> where that got me. If I get burning, I'll reduce the voltage/current.
> If I get nothing, I'll increase the voltage (dropping it from the 12v
> supply on the PSU down to 6, 8, 10 etc. using a simple voltage divider
> and big resistors) and see what I can do. It's a relatively small
> investment for me (apart from the chemistry from LPKF) because I have
> a lot of the stuff on-hand. I use CAT4101's in LED drivers, and I have
> a spare 50 or so of them lying around :)

That way you can simple use 3.3V output and a big tank where you adjust
distance between anodes and cathode. 

Simao