NOAC Power Regulation?

Skidlz · Post by **Skidlz** » Wed Jan 21, 2009 6:56 pm

I'm building a Super Joy III NOAC into a standard project enclosure and I need to know how the power regulator should be built. I have what seems to be the original power supply (4.8v 100mA) though it measures 8.35v. It's going to be attached like this:

9v in being the power supply.
Is this correct? I've seen schematics that use caps from .1uf to 100uf and some are not balanced. Plus some don't use a diode.
Any help would be appreciated.
Thanks

timmeh87 · Post by **timmeh87** » Thu Jan 22, 2009 1:22 am

Most people dont use the diode

XCVG · Post by **XCVG** » Thu Jan 22, 2009 10:15 am

What's the diode for?

Skidlz · Post by **Skidlz** » Thu Jan 22, 2009 12:28 pm

XCVG wrote:What's the diode for?

D1 protects the 7805 in case the input voltage is higher than the output, for example if the input is de-powered while the output capacitor C5 is charged. Without the diode, the 78XX could possibly be damaged by reversed voltage. With the 7805 the diode could probably be left out while for higher voltages than 5V it is definitly recomended.

taken from http://www.41hz.com/main.aspx?pageID=115 I don't get it but I had a 14001 and some spare room on my PCB so I added it.

timmeh87 · Post by **timmeh87** » Thu Jan 22, 2009 5:52 pm

If you have enough input capacitance though then the power wont drop as fast when you shut it off and you might be ok. Output capacitance is probably pretty high though once you hook it up to all your kit.

Skidlz · Post by **Skidlz** » Thu Jan 22, 2009 6:40 pm

I'm just piece-mealing schematics here so I don't know much, period. What would be a good value for the output cap and what would be the downside of 10uf? I already soldered it all together so I would have to go through a somewhat messy desolder to replace it.