Rectifiers

[pyrre]

@ motorollin
Why not build a pico psu inside an a500 psu box...
pico psu wil provide 30, 60 or even 120W of power...
discrete packaging inside the a500 psu box as a bonus...

[Oliver]

pyrre wrote:
Why not build a pico psu inside an a500 psu box...

I think the point was to eliminate the need for a sizeable external PSU box, by placing all components in a plugpack.

Zeners do not make very good regulators. They are small and cheap, and can be useful for low power loads. They can be improved with use of output transistors. It also requires a little more effort in design to include good failure modes. In terms of voltage regulation, the zener provides a reference output which sits on its reverse breakdown IV load line, which performs less well than a linear regulator.

There is pleanty of information about zener regulators online, including various designs. I still use zener regs for some applications.

[motorollin]

Oliver wrote:

pyrre wrote:
Why not build a pico psu inside an a500 psu box...

I think the point was to eliminate the need for a sizeable external PSU box, by placing all components in a plugpack.

Indeed. The only other way would be to build the PicoPSU in to the Amiga itself and then have a 12v supply in plugpack form factor which powers the PicoPSU. The problem is though that I have had a PicoPSU before and couldn't find a 12v plugpack PSU with enough current to power the PicoPSU.

My knowledge of electronics is not good enough to be sure anything I design would be safe. I thought this would be more simple to design, but given the possibility of it failing I'll have to just leave it I think.

[Oliver]

motorollin wrote:
...given the possibility of it failing I'll have to just leave it I think.

Lots of people design these things without any regard for failure modes. Most of the time it is fine, too. Personally, I think if you can understand how to do so, the small expense in additional components is well worth it. If you are willing to read an electronics text, then low power linear PSU design is not an unmanageable goal. I wouldn't adivise making one without at least a basic understanding of what is involved, though.

[motorollin]

I'm prepared to do some reading but at the moment I don't have time. My degree is taking most of my spare time so this will have to be relegated to a summer holiday project :-(

[Oliver]

motorollin wrote:
My degree is taking most of my spare time...

Yeah, that's pretty much what I had expected. I was actually a little surprised that you would be taking on a design project at this time.

All the best for your studies.

[motorollin]

Oliver wrote:

motorollin wrote:
My degree is taking most of my spare time...

Yeah, that's pretty much what I had expected. I was actually a little surprised that you would be taking on a design project at this time.

Well, I didn't think it would take so much designing when I first had the idea ;-)

Oliver wrote:
All the best for your studies.

Thanks!

[pyrre]

here is a link to some psu's that might get you started.
I do not know if you have investigated upon the possibilities from mini-itx. But some of the psu's looks useful...
Some of them are made for var environments as well, and should provide sufficient fail safes for home use.

Good luck on your project.
Hope it helps.

[JLF65]

pyrre wrote:
here is a link to some psu's that might get you started.
I do not know if you have investigated upon the possibilities from mini-itx. But some of the psu's looks useful...
Some of them are made for var environments as well, and should provide sufficient fail safes for home use.

Good luck on your project.
Hope it helps.

I already posted a link to that and he claimed it wasn't what he wanted.