easiest way to get +-12 volts from a car battery? - Electronic Circuits Projects Diagrams Free

Death By Bass · 26th August 2006, 12:10 PM

not sure how much current I need, probably 1 amp each should do it.

I know national semiconductors do a regulator, that with a switchmode transformer will give +-12 volts, but these parts aren't easy to come by...

I'll measure how much current I actually need at -12volts, it may not be that much.

also, +-11 volts seems to be enough anyway, as thats what the powersupply I'm looking to replace gives anyway.

cheers!

edit:

-12 volts @ 20mA is all I seem to need...

Death By Bass · 26th August 2006, 12:41 PM

+12 volts @ 30mA looks like it would be enough aswell

Dr.EM · 26th August 2006, 01:12 PM

This might do the trick, I made it once and it does work (was powering an op-amp)

http://sound.westhost.com/project95.htm

Hero999 · 26th August 2006, 03:06 PM

What are you building?

There might be a simpler way to convert your project so it will run of one single 12V supply.

Death By Bass · 26th August 2006, 11:52 PM

Quote:

Originally Posted by Hero999

What are you building?

There might be a simpler way to convert your project so it will run of one single 12V supply.

its a home DVD player, that has +5 +12 and -12 volt rails...

the +-12 seems to only be for the circuitry... the +5 volts controls everything else, like motors and the display.

Analog · 27th August 2006, 11:08 AM

You need a dc/dc converter module. Digikey and others sell them. You must also figure out the current requirements to size one.

Death By Bass · 28th August 2006, 11:53 AM

Quote:

Originally Posted by Analog

You need a dc/dc converter module. Digikey and others sell them. You must also figure out the current requirements to size one.

like I said... +-12 volts at under 100mA...

*looks around the room*
*pulls some PCBs out from under my bed*

hmm...

+5volts in, +-15 volts out? close

lol

Hero999 · 28th August 2006, 12:58 PM

Easy, add a LM7912 to the -15V supply.

Death By Bass · 28th August 2006, 09:46 PM

Quote:

Originally Posted by Hero999

Easy, add a LM7912 to the -15V supply.

be even easier to just buy a 10-15volt input, +-12volt output module...

rather than use the module I have, plus three regulators, and a handfull of capacitors...

Hero999 · 28th August 2006, 11:02 PM

Looks like you've answerd your own question then.

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26th August 2006, 12:10 PM	#1
Death By Bass	easiest way to get +-12 volts from a car battery? not sure how much current I need, probably 1 amp each should do it. I know national semiconductors do a regulator, that with a switchmode transformer will give +-12 volts, but these parts aren't easy to come by... I'll measure how much current I actually need at -12volts, it may not be that much. also, +-11 volts seems to be enough anyway, as thats what the powersupply I'm looking to replace gives anyway. cheers! edit: -12 volts @ 20mA is all I seem to need... Last edited by Death By Bass; 26th August 2006 at 12:18 PM.

26th August 2006, 12:41 PM	#2
Death By Bass	+12 volts @ 30mA looks like it would be enough aswell

26th August 2006, 01:12 PM	#3
Dr.EM	This might do the trick, I made it once and it does work (was powering an op-amp) http://sound.westhost.com/project95.htm __________________ Angry!? I'm absolutely electrolytic! Music web page: http://www.music-playground.net/artist/drem/

26th August 2006, 03:06 PM	#4
Hero999	What are you building? There might be a simpler way to convert your project so it will run of one single 12V supply. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

27th August 2006, 11:08 AM	#6
Analog	You need a dc/dc converter module. Digikey and others sell them. You must also figure out the current requirements to size one. __________________ "Everything that is done in the world is done by hope." -Martin Luther "There are two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle."-Albert Einstein

28th August 2006, 12:58 PM	#8
Hero999	Easy, add a LM7912 to the -15V supply. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

28th August 2006, 11:02 PM	#10
Hero999	Looks like you've answerd your own question then. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.