As the title says. I have some prop electronics that need a 9 volt source, but all I have is 12V. Anyone know of a easy way to solve the issue?
-Gary
-Gary
Taking 12V DC to 9V DC - Anyone know how?
- Thread starter Gary Weaver II
- Start date
<div class='quotetop'>(gw2tulsa @ Aug 1 2006, 04:16 PM) [snapback]1292026[/snapback]</div>
Gary, There are several ways to get there. Some more information on the load would be helpful? (i.e. current draw at 9VDC)
Here is one source for a kit. It's very low cost. http://store.qkits.com/moreinfo.cfm/fk805
Bobby
Gary, There are several ways to get there. Some more information on the load would be helpful? (i.e. current draw at 9VDC)
Here is one source for a kit. It's very low cost. http://store.qkits.com/moreinfo.cfm/fk805
Bobby
DL 44 Blaster
Sr Member
A step down transformer would be the best place to start. I'm no electrician, but know just enough to get me into trouble 
Steve
Steve
Capt MarVell
Sr Member
A step down transformer isn't going to help with DC, transformers are for AC. You need a voltage regulator circuit. Knowing the current draw would help though, to know just what package is needed. A LM7809 would probably work OK with a 12VDC input and 1A current; an LM78L09 (smaller package) would work with the same voltages but supplies considerably less current. A voltage regulator is a 3-leg device that has an input, ground, and output. The input should usually be a few volts higher than the output, so 12 to 9 works OK. A capacitor on the inputs and outputs provides some filtering of any AC component.
A sample circuit and further info can be found at http://www.eidusa.com/Electronics_Voltage_Regulator.htm Also, the kit linked to above is probably a good starting point.
Jim
A sample circuit and further info can be found at http://www.eidusa.com/Electronics_Voltage_Regulator.htm Also, the kit linked to above is probably a good starting point.
Jim
Buy a 9v battery?
DC-to-DC converter can do it...but again, it all depends on your needs and cost.
Sean
Sean
Great_Bizarro
Sr Member
Capt MarVell is correct, 9v. regulator. Just make sure the regulator you use will carry the amperage required. And as Darth Mawr asked, why not use a 9v battery? I have a prop I am using 2-AA for leds and a 9V for audio.
I stumbled across a possible solution this morning. Its a converter for MP3 and CD Players. You just plug it into your car lighter and then select your output voltage. This SHOULD work for what I need to do.
I'll be able to test a little more once my sound board comes in this weekend.
-Gary
I'll be able to test a little more once my sound board comes in this weekend.
-Gary
Jedi Lawja
Well-Known Member
If he just wants to drop the voltage by 3V, couldn't he just use a resistor?
Jay
Jay
Capt MarVell
Sr Member
With a dropping resistor, if the input voltage varies, so will the output. The regulator will do a better job of clamping the voltage to 9V no matter the input.
Sounds like the converter he found will likely do the job.
Jim
Sounds like the converter he found will likely do the job.
Jim
<div class='quotetop'>(Jedi Lawja @ Aug 2 2006, 09:14 AM) [snapback]1292408[/snapback]</div>
With the dropping resistor the voltage will drop as the batteries discharge. He would get 9vdc when the batteries are at full charge only. The resistor would also waste quite a bit of charge heating up. Jim is correct that a dc to dc converter will do a much better job. Some of the new ones will raise the batteries voltage to 9vdc even when they drop below 9vdc.
Bobby
With the dropping resistor the voltage will drop as the batteries discharge. He would get 9vdc when the batteries are at full charge only. The resistor would also waste quite a bit of charge heating up. Jim is correct that a dc to dc converter will do a much better job. Some of the new ones will raise the batteries voltage to 9vdc even when they drop below 9vdc.
Bobby
