| Author |
 Topic  |
|
|
nosi0
Gold Member
Netherlands
511 Posts |
 Posted - 07/22/2009 : 13:53:21
|
I was wondering if anybody could help me find a design for a galvanically separated power supply. or describe how one works. after reading this thread. i became interested in making my own power supply. I really want one of these powersupplies but i'm not going to pay 180 euros for it.
All i know so far is that each connection uses it's own torodial transformer.
Nosi.
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/22/2009 : 14:40:31
|
It is simply a number of separate power supplies contained in one box. Probably the cheapest way to build one would be to use the circuit in the other thread (make 8 of them), and power each of them with one of the 11V windings on this: http://www.smallbearelec.com/Detail.bok?no=597
Take great care to ensure the heatsinks on the 7809 regulators are electrically isolated.
Doing this will remove any chance of hum. |
 |
|
|
nosi0
Gold Member
Netherlands
511 Posts |
Posted - 07/22/2009 : 15:42:43
|
Thanks a lot Laurie! With electrically isolated you mean that the heatsink is not touching any metal including ground correct?
On the transformer the Green and Black are AC and then all the brown ones are 11v windings like you said?
Thanks, Nosi |
|
|
|
nosi0
Gold Member
Netherlands
511 Posts |
Posted - 07/22/2009 : 22:41:48
|
| I did some more research, seems like a achievable project i'll get started it once i have settled into university. Thanks for the help Laurie. |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/22/2009 : 22:46:32
|
quote:
Originally posted by nosi0
Thanks a lot Laurie! With electrically isolated you mean that the heatsink is not touching any metal including ground correct?
Yep. On the 7809, the heatsink tag is at groundpotential. it is essential that the tags of the many 7809 devices don't touch one another.
quote:
On the transformer the Green and Black are AC and then all the brown ones are 11v windings like you said?
Not sure... Have to check out the specs with the vendor. And if you were to use the transformer from Small Bear, there is a 220/240V primary version for a few more bucks.
|
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/22/2009 : 22:47:49
|
quote:
Originally posted by nosi0
I did some more research, seems like a achievable project i'll get started it once i have settled into university. Thanks for the help Laurie.
No worries! If you wanted a PCB layout for this, let me know. |
|
|
|
nosi0
Gold Member
Netherlands
511 Posts |
Posted - 07/26/2009 : 12:45:43
|
Thanks for the help Laurie, i got the PCB layout in my head so thats not a problem. Once ive finished moving from Taiwan to the Netherlands i think i'm going to order a set of two or three. Any ideas what i should do with the 9V 2A outlet? i don't have any 9VAC pedals. i guess i could use those outlets for LED's to light up the pedalboard. if i used resistors to make the LED's usable with 9V will it matter how many amps are created by the transformer or will it just use what it needs. what i'm asking is if the led's will blow on a 2A supply. I need to find a 2A bridge ofcourse in that case.
Thanks, Nosi |
Edited by - nosi0 on 07/26/2009 16:46:51 |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/26/2009 : 18:02:42
|
quote:
Originally posted by nosi0
what i'm asking is if the led's will blow on a 2A supply. I need to find a 2A bridge ofcourse in that case.
Thanks, Nosi
No, the LEDs will be fine. Use a bridge rectifier and a filter cap on the 9VAC winding - that will give about 12VDC. You will need a 1K resistor in series with each LED to limit the current. |
|
|
| |
Topic |
|
Galvanically separated power supply
