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Gear / Technical Help => Remote Power => Topic started by: lds490 on January 13, 2005, 11:39:53 AM

Title: How to: regulate voltage?
Post by: lds490 on January 13, 2005, 11:39:53 AM

I'm investigating power options for my festival rig.  I've got an extra DVD battery (12 Volt, similar to the Wal-mart battery) that I'd like to use for my external hard drive.  The problem is the hard drive runs on 5 volts.  Can I buy or build something that will step down the power from 12V to 5V?  Can anyone here explain how to me?

Thanks.

Title: Re: How to: regulate voltage?
Post by: BJ on January 13, 2005, 11:43:03 AM

yea..take a look at the jb3 pwer II thread....leegeddy is building a VR box...shoot him a pm for more details...but there is some info in that thread

Title: Re: How to: regulate voltage?
Post by: fozzy on January 13, 2005, 12:05:19 PM

There are losts of ways to regulate voltage.  how handy are you at soldering?

1.) leegeddy power solution
2.) build your own voltage regulator from component parts.
3.) hack a fixed or adjustable car adapter.

Title: Re: How to: regulate voltage?
Post by: Lil Kim Jong-Il on January 14, 2005, 03:49:33 PM

google for:


LM7805 5V fixed voltage regulator
LM317 voltage regulator that can be adjusted to other voltages

The datasheet for the 7805 will show a circuit diagram.

a few dollars worth of parts and very simple assembly. 

Title: Re: How to: regulate voltage?
Post by: fozzy on January 14, 2005, 05:06:43 PM

Quote from: Maynard G. Beatnik on January 14, 2005, 03:49:33 PM

google for:


LM7805 5V fixed voltage regulator
LM317 voltage regulator that can be adjusted to other voltages

The datasheet for the 7805 will show a circuit diagram.

a few dollars worth of parts and very simple assembly. 

i prefer the LT1086 b/c it can handle 1.5 amps and is also of the LDO (low drop) variety too bad they don't make it in a surface mount package. 

Title: Re: How to: regulate voltage?
Post by: dklein on January 15, 2005, 02:57:17 PM

If the current draw is significant you'll be generating quite a bit of heat dropping from 12 >5 with a linear regulator.  A lower voltage battery will help, otherwise you'll need to think about heat sinking if you make it.  A car adapter is where I'd start - it's cheap and usually delivers 500-1000 mA. 

I googled power consumption and found that 2.5 watts is typical.
Watts = Volts x Amps

So 500 mA should do it and the car adapter is your friend.

Another spot I just checked spec'd start up at 1000, seeking at 500 and idle at 250 mA.