Anybody know any schematics and/or layouts that will put out 12v DC and do all the filtering I need? I'm in the U.S., so 110/120V is good.
Transformer -> Rectifier - > Filtering Capacitor -> LM78XX Regulator -> Bypass Capacitor = Basic general purpose power supply! The LM78XX is a three pin regulator IC that you can get for different voltages, the XX is the voltage. For example, LM7809, LM7812. (I think you knew that but w/e)
http://www.generalguitargadgets.com/pdf/ggg_reg_power_supply.pdf
Make sure you get the right transformer, a 12V transformer does not mean 12VDC after filtering but 12VAC RMS, usually.
Thanks JKowalski :icon_mrgreen:
I'm going to try to make a schematic and layout and I'll post it here to make sure I got it right :-\
Power scares me :icon_sad:
Hey wait.. why can't I just use the GGG one you posted w/o the 9v regulator? I'll need 6v too, so instead of diving the voltage, can't I just tap those... secondaries (I think that is what they are called)...
Looks like no leads showing here.
http://www.smallbearelec.com/Detail.bok?no=339
On the GGG page^, it looks like the secondary center-tap, maybe could be used to get 6vdc, but you'd have to Rectify and filter and regulate again.
Instead, a 6vdc regulator could take an existing voltage and convert it to DC.
Never tried it.
Looks like a tap could be at the diode regulator, or at the 9vdc regulator output.
Tapping the 6v circuit at the same place the 9v circuit taps means you get as much current as the 6v regulator can handle [or the transformer], after means the 9v regulator gets the current of both the outlet taps and running the 6v regulator.
I'd test for need of a heat sink for sure on the 6vdc, it's got to drop more voltage, so more heat sinking might be needed.
Well forgetting that last comment, how about thes
Transfomer:
http://mouser.com/ProductDetail/Hammond/164G16/?qs=JhldWgE%2f6bt%252bWrzyJ9IHwg%3d%3d
Diodes (4x):
http://www.fairchildsemi.com/ds/1N/1N4001.pdf
7812:
http://www.fairchildsemi.com/ds/LM%2FLM7812A.pdf
With corresponding caps.
Quote from: mth5044 on January 26, 2010, 12:12:47 AM
Well forgetting that last comment, how about thes
Transfomer:
http://mouser.com/ProductDetail/Hammond/164G16/?qs=JhldWgE%2f6bt%252bWrzyJ9IHwg%3d%3d
Diodes (4x):
http://www.fairchildsemi.com/ds/1N/1N4001.pdf
7812:
http://www.fairchildsemi.com/ds/LM%2FLM7812A.pdf
With corresponding caps.
Everything there looks good. However, the transformer is a little overkill (overpriced). I'm not sure what your gonna use the P/S for, but if you only need an amp or less current you can use any wallwart transformer 12-24 volts @ 1amp to power the regulator. You can buy one at the local thrift store, crack it open, and mount it to a perfboard along with the rest of the circuit. For the 6v tap, you can use a voltage divider (ie: 2 100k resistors across the 12v and ground, tap the middle for 6v) as long as you don't need much current for the 6v tap. If you need more current for the 6v tap, you can connect a 7805 regulator, use resistors to adjust the regulator to 6v and you're done. Or...use a LM317T adjustable regulator for the 6V tap if adjusting the 7805 introduces noise. As you can see there are many ways to get what you need. Search google for DIY power supplies and you'll find many good designs.
Hope this helps!
Have you read "Power Supplies Basics" at geofex yet?
It covers a whole lot of the ground for you, and is relatively easy to digest.
Quote from: R.G. on January 26, 2010, 12:47:17 AM
Have you read "Power Supplies Basics" at geofex yet?
This is like when you go to the dentist and they ask if you've been flossing :icon_redface:
You know you haven't, they know you haven't, but you usually tell them you did :icon_lol:
Off to GEOFEX. :)
Quote from: mth5044 on January 26, 2010, 11:44:58 AM
You know you haven't, they know you haven't, but you usually tell them you did :icon_lol:
Ahahahaha, I love that analogy ;D
Quote from: JKowalski on January 26, 2010, 12:08:18 PM
Ahahahaha, I love that analogy ;D
:icon_lol:
Quote from: compuwade on January 26, 2010, 12:34:59 AM
Everything there looks good. However, the transformer is a little overkill (overpriced). I'm not sure what your gonna use the P/S for, but if you only need an amp or less current you can use any wallwart transformer 12-24 volts @ 1amp to power the regulator. You can buy one at the local thrift store, crack it open, and mount it to a perfboard along with the rest of the circuit. For the 6v tap, you can use a voltage divider (ie: 2 100k resistors across the 12v and ground, tap the middle for 6v) as long as you don't need much current for the 6v tap. If you need more current for the 6v tap, you can connect a 7805 regulator, use resistors to adjust the regulator to 6v and you're done. Or...use a LM317T adjustable regulator for the 6V tap if adjusting the 7805 introduces noise. As you can see there are many ways to get what you need. Search google for DIY power supplies and you'll find many good designs.
Hope this helps!
That is a good idea, to just crack one open and use the circuit. If I weren't so dead set on making it myself, I would definitely do that.
As for the overkill transformer, how about this one?
http://mouser.com/ProductDetail/Hammond/161G16/?qs=sGAEpiMZZMv4oUrzpPKU3L2j9JyvMp7Oviud9IttgSU%3d
A couple bucks cheaper.
Quote from: petemoore on January 26, 2010, 12:04:11 AM
Looks like no leads showing here.
http://www.smallbearelec.com/Detail.bok?no=339
On the GGG page^, it looks like the secondary center-tap, maybe could be used to get 6vdc, but you'd have to Rectify and filter and regulate again.
Instead, a 6vdc regulator could take an existing voltage and convert it to DC.
Never tried it.
Looks like a tap could be at the diode regulator, or at the 9vdc regulator output.
Tapping the 6v circuit at the same place the 9v circuit taps means you get as much current as the 6v regulator can handle [or the transformer], after means the 9v regulator gets the current of both the outlet taps and running the 6v regulator.
I'd test for need of a heat sink for sure on the 6vdc, it's got to drop more voltage, so more heat sinking might be needed.
So taping the center for 9 and 6v would be a bad idea? I forgot about the heat sink thing too, so I'll have to keep that in consideration, thanks! I don't know how I missed this post earlier.
So hopefully one final question that I don't think I saw in the geofex article. The primary voltage rating... Is that like the max power the transformer can take? There seems to be 115V and 230V. I know 230V is for some European settings, but I thought the U.S. had 120V coming out of the wall? Is 115V ok?
It looks like that's the best priced transformer at mouser for what you need. It'll work just fine. Some transformers have primary taps for Europe and the US (ie: 220,230,240 for international, 110,115,120 for US). When you recieve the transformer it will come with a wiring diagram for 230 and 115. Just use the 115 tap and you're good to go. I assume that the 115 rating is in case your wall voltage is slightly higher than 110 volts. Which most are. Mine is actually around 117v. But I don't have any issues with anything I use.
Doesn't get any much simpler than this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-534
I just recieved it.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-536
~16 buxx gets you ~1 amp of 12vdc.
Quote from: compuwade on January 26, 2010, 02:35:07 PM
It looks like that's the best priced transformer at mouser for what you need. It'll work just fine. Some transformers have primary taps for Europe and the US (ie: 220,230,240 for international, 110,115,120 for US). When you recieve the transformer it will come with a wiring diagram for 230 and 115. Just use the 115 tap and you're good to go. I assume that the 115 rating is in case your wall voltage is slightly higher than 110 volts. Which most are. Mine is actually around 117v. But I don't have any issues with anything I use.
Good to know!
Quote from: petemoore on January 26, 2010, 03:29:51 PM
Doesn't get any much simpler than this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-534
I just recieved it.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-536
~16 buxx gets you ~1 amp of 12vdc.
Woah I thought desk power units were more expensive than that. In any case, I'll be putting this power in an effect, so unless I take the power out of the enclosure, it may be easier just to build one. I'll keep these in mind though when I need a desk unit!
Okay here we go!
(http://i246.photobucket.com/albums/gg114/mth5044/BisonPower2schematic.jpg)
(http://i246.photobucket.com/albums/gg114/mth5044/Powerboards.jpg)
Transformer: http://mouser.com/ProductDetail/Hammond/161G16/?qs=sGAEpiMZZMv4oUrzpPKU3L2j9JyvMp7Oviud9IttgSU%3d
Not sure if i'll need the heatsinks on the regulators.. I made these in hopes that I wouldn't :(
Bah, just realized I have the regulators messed up. I'll put up the fixed ones in a few minutes.
EDIT: ok, the layout is fixed from the problem I saw.. unfortuantly it meant I had to put in the dreaded jumper overtop the 7805. Oh well.
It looks like you have the 5 and 6 volt outputs backwards.
As far as heatsinks...It depends on your input voltage. 16v rectified could be as much as 20v after the 1st filter or even more. If this is the case the diferences in input voltages to the regulator output voltages will result in heat. You should be good with the 12v regulator but the 5v regulator could get hot if your application requires any real current.
Quote from: compuwade on January 26, 2010, 05:28:08 PM
It looks like you have the 5 and 6 volt outputs backwards.
As far as heatsinks...It depends on your input voltage. 16v rectified could be as much as 20v after the 1st filter or even more. If this is the case the diferences in input voltages to the regulator output voltages will result in heat. You should be good with the 12v regulator but the 5v regulator could get hot if your application requires any real current.
I fixed that on the second one too, thanks for pointing it out though.
I'm not sure if the circuit is going to require any real current.. it'll be be a bunch of stuff thrown together. What would be a real current? The only thing the 5v will be feeding is 4 pt2399 chips and I can't find a current draw for them in the datasheet.. I may be missing it though
PT2399: http://www.datasheetcatalog.org/datasheet/PrincetonTechnologyCorporation/mXyzsyzt.pdf
7805 : http://www.fairchildsemi.com/ds/LM/LM7805.pdf
Just out of curiosity, why wouldn't i need a fuse for this circuit?
You want 100n caps to ground on either side of all the regulators to help quieten them down and you can also use an opamp for the 6V supply to get a low impedance output or use a 5V regulator with resistors to lift it to 6V. Maybe even make your first 220uf 2 x 100uf with a 100 ohm resitor between them as a low pass to get rid of a little ripple.
And a fuse on the mains couldnt hurt anything...
Quote from: mth5044 on January 26, 2010, 05:40:13 PM
I'm not sure if the circuit is going to require any real current.. it'll be be a bunch of stuff thrown together. What would be a real current? The only thing the 5v will be feeding is 4 pt2399 chips and I can't find a current draw for them in the datasheet.. I may be missing it though
PT2399: http://www.datasheetcatalog.org/datasheet/PrincetonTechnologyCorporation/mXyzsyzt.pdf
There are several PT2399 datasheets floating around. The 16 page version (1.4) is the most thorough: http://www.tubes.it/PT2399.pdf
The supply current is 30-40mA. So let's say 40mA each, or 160mA total. If I've got this right, you take the 12v output from your 7812 minus 5v after your 7805 = 7v to burn off. 7v multiplied by 0.16 amps = 1.12 watts of heat dissipation minimum from the 7805.
I don't know if that requires a heatsink, though, sorry...
Mike
Quote from: sean k on January 26, 2010, 05:57:02 PM
You want 100n caps to ground on either side of all the regulators to help quieten them down and you can also use an opamp for the 6V supply to get a low impedance output or use a 5V regulator with resistors to lift it to 6V. Maybe even make your first 220uf 2 x 100uf with a 100 ohm resitor between them as a low pass to get rid of a little ripple.
Alright, I added a 100n cap between the 220uF and pin 1 of the 12v regulator and one right after it before the 100uF cap. I thought that one would be considered as both before the 5v and after the 12v :icon_lol: Then there is one after the 5v regulator already. I'm not too sure what you mean about the 100ohm resistor though? Do you think it is something really necessary, or just extra caution?
Quote from: .Mike on January 26, 2010, 06:07:56 PM
There are several PT2399 datasheets floating around. The 16 page version (1.4) is the most thorough: http://www.tubes.it/PT2399.pdf
The supply current is 30-40mA. So let's say 40mA each, or 160mA total. If I've got this right, you take the 12v output from your 7812 minus 5v after your 7805 = 7v to burn off. 7v multiplied by 0.16 amps = 1.12 watts of heat dissipation minimum from the 7805.
I don't know if that requires a heatsink, though, sorry...
Mike
Whaaat I didn't know that there was an extended data sheet! That is awesome. I don't know if that means I need a heat sink either, but thanks for doing the math!
Quote from: Brymus on January 26, 2010, 06:00:35 PM
And a fuse on the mains couldnt hurt anything...
I don't know the first thing about picking out the right fuse, so any idea what ratings I should look for? I think it goes between the AC cord and pin 1 of the transformer, right?
Thanks everyone :)
current tends to vary and can be controlled, volume control, bass control etc.
Starting with more Ma than you need or with low volume, testing chip temperature as volume/current is increased [quick touch, fairly quick touch [sometimes that second one'll getcha, leave a burn mark..].
Personally, I'd put a heat sink on AT LEAST the 5 volt, and as you are using a bridge rectifier, I'd want one on the 12V rectifier as well (you get more voltage out of a bridge than a full wave). But I am far from being an expert in this, I just like to over engineer whenever possible.
Gabriel