Bipolar Variable Power supply for protoboard

jman 31 · 23rd March 2009, 08:19 PM

I guess the title says it all. I want to build a bipolar variable Power supply somewhere between 5 and 30 dc volts that I can plug into my protoboard for various projects. I was looking at THIS ONE, but I wanted something that was variable on the spot. If someone could point me to a good one I would really appreciate it.

Thanks
Jman

mjf · 23rd March 2009, 10:38 PM

hello.
simple and classic: have a look at power supplies with lm317/lm337 variable regulators (for preamp projects and so.....)
greetings...........

AndrewT · 23rd March 2009, 10:52 PM

try this Forum.

jman 31 · 23rd March 2009, 11:15 PM

Quote:

Originally posted by AndrewT
try this Forum.

Wow, never would have thought of that.

I did a search but I didn't really have any parameters other than the title of this thread. I will do it again now that mjf has given me a meaningful response.

TechGuy · 24th March 2009, 12:13 AM

Your better off purchasing either an open frame or closed frame switching power supply. A commerical product will include over-current sensing, provide multiple voltages and have a higher current output.

The LM317 LM78xx are really designed for very low output current, and can't handle large voltage differences been in the input voltage and the output voltage.

Here is a low cost Open Frame SMPS from Artesyn
Mouser 826-NFS40-7608J $49.22

The only import feature is make sure the power supply you choose can operation with no load. look for PS that can operate at 0A (ie 5V 0-3.2A). Otherwise you need to attach a resistor to produce some load. SMPS that have a minimum current load will switch immediately off, if there is no load present at power on.

AndrewT · 24th March 2009, 09:34 AM

"voltage regulator" brought up 3201 threads.
"variable voltage regulator" brought up 136 threads.
Start searching instead of just clicking "I have searched" icon

jman 31 · 24th March 2009, 12:13 PM

Quote:

Originally posted by AndrewT
"voltage regulator" brought up 3201 threads.
"variable voltage regulator" brought up 136 threads.
Start searching instead of just clicking "I have searched" icon

OK so your one of those. I get it. I searched "bipolar power supply breadboard". three results. None that helped. Have you ever realized that sifting through 3,201 threads or even 136 threads to try to find exactly what you are after is a daunting task. What does it hurt to ask directly about a certain item instead of guessing which one is the right one for me. And if you don't want to help, don't!

TheSeekerr · 24th March 2009, 01:18 PM

Hi,

You haven't given enough information. How much current does it need to supply? 100mA? 500? 5 amps? Tell us that, and maybe we can tell you what you want to build.

jman 31 · 24th March 2009, 02:50 PM

Quote:

Originally posted by TheSeekerr
Hi,

You haven't given enough information. How much current does it need to supply? 100mA? 500? 5 amps? Tell us that, and maybe we can tell you what you want to build.

Sorry about that. You are absolutely right. Mostly what I am doing is small 9 volt projects. Stompboxes for guitars, headphone amps, and the like so I would say 100ma would cover it. I probably really only need it to cover up to about 18v.

mjf · 24th March 2009, 03:36 PM

hello.
i think there are some examples in the datasheet of the lm317 and lm337.................
greetings...............

23rd March 2009, 08:19 PM	#1
jman 31 diyAudio Member Join Date: Oct 2008 Location: Florida	Bipolar Variable Power supply for protoboard I guess the title says it all. I want to build a bipolar variable Power supply somewhere between 5 and 30 dc volts that I can plug into my protoboard for various projects. I was looking at THIS ONE, but I wanted something that was variable on the spot. If someone could point me to a good one I would really appreciate it. Thanks Jman

23rd March 2009, 10:52 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	try this Forum. __________________ regards Andrew T.

24th March 2009, 09:34 AM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	"voltage regulator" brought up 3201 threads. "variable voltage regulator" brought up 136 threads. Start searching instead of just clicking "I have searched" icon __________________ regards Andrew T.

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23rd March 2009, 10:38 PM	#2
mjf diyAudio Member Join Date: Jan 2009 Location: upper austria/near linz	hello. simple and classic: have a look at power supplies with lm317/lm337 variable regulators (for preamp projects and so.....) greetings...........

24th March 2009, 12:13 AM	#5
TechGuy diyAudio Member Join Date: Apr 2006 Location: Connecticut	Your better off purchasing either an open frame or closed frame switching power supply. A commerical product will include over-current sensing, provide multiple voltages and have a higher current output. The LM317 LM78xx are really designed for very low output current, and can't handle large voltage differences been in the input voltage and the output voltage. Here is a low cost Open Frame SMPS from Artesyn Mouser 826-NFS40-7608J $49.22 The only import feature is make sure the power supply you choose can operation with no load. look for PS that can operate at 0A (ie 5V 0-3.2A). Otherwise you need to attach a resistor to produce some load. SMPS that have a minimum current load will switch immediately off, if there is no load present at power on.

24th March 2009, 01:18 PM	#8
TheSeekerr diyAudio Member Join Date: Jan 2008	Hi, You haven't given enough information. How much current does it need to supply? 100mA? 500? 5 amps? Tell us that, and maybe we can tell you what you want to build.

24th March 2009, 03:36 PM	#10
mjf diyAudio Member Join Date: Jan 2009 Location: upper austria/near linz	hello. i think there are some examples in the datasheet of the lm317 and lm337................. greetings...............

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