Dual Rail PSU

[odessa]

Hi guys,

Thought I would share some of my latest stuff. I've been learning about op amps and audio amps so decided I would build one. The most important thing with any amp is a good PSU...so I thought I would make a Dual rail one. Heres the result. The 78** and 79** can be replace to give any voltage required.

Schematic in EAGLE

12vdc-PSU.jpg (31.82 KiB) Viewed 11410 times

Board layed out ready to print and etch

board.jpg (46.32 KiB) Viewed 11410 times

Voila ... Finished :)

board1.jpg (67.98 KiB) Viewed 11410 times

My best layout yet ... I love making pcb's

board2.jpg (58.6 KiB) Viewed 11410 times

Really pleased with the results here

I didn't actually need this board for the amp chip I picked for my first amp project but its great having it standing by for a future amp project ( which will be very soon ) and a dual rail supply is also good to have whilst experimenting

Remember ... never put your board onto a blob of hot glue :(

board3.jpg (64.62 KiB) Viewed 11410 times

[brad]

This is one of the circuits we teach for dual rail PSU's!

Did you know that the two diodes D1 and D2 are there for overvoltage protection when you first turn the circuit on - once both regs are on, the diodes are effectively not even there.

[odessa]

Yes, I was looking at various designs online and found this one to be the best .

Do you have any links for a variable dual rail PSU Brad ? I wouldn't mind making one for my workshop

Jay

[brad]

Hmm, I think you can just replace the 7805 / 7905 regs with higher voltage ones and then have a voltage divider network going to the GND pins rather than connecting them directly to ground. Then you can vary the reference voltage on the GND pin to vary the regulated output voltage.

[MrDEB]

here is a link to a nice variable lab supply using the LM317
I would add some output caps and protection diodes (see discussion and/or data sheet)
http://digital-diy.com/Projects/ten-buc ... upply.html
Hope this helps

[brad]

Nice work MrDEB!