Pages: [1]   Go Down
Author Topic: <SOLVED> Another Noob Power Question  (Read 438 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 1
Posts: 30
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

If you start out with a regulated power source, say 35A of 12V from a converted ATX power supply

In a simple voltage divider as I understand it anyway,

                       R1              R2
+12V        o----\/\/\----o----\/\/\------o  GND
             V1               V2                

How do I find out what values for R1 and R2  if  V1 = 12V and V2 = 7.5 @ 2.0 Amps

R1 = ?
R2 = ?
V1 = 12V
V2 = 7.5V


And since the V1 = regulated 12V and isn't supposed to fluctuate (too much)
would I not get a fairly constant value from V2 ?

This would allow for powering a couple of legacy devices that require a regulated 7.5 V as well as powering the arduino itself at 7.5V instead of 12V making arduino regulator work cooler.

I'm gonna burn up so much stuff... better tripple my parts order!

Thanks guys...
« Last Edit: October 17, 2012, 11:13:38 pm by NobleNoob » Logged

the land of sun+snow
Offline Offline
Faraday Member
**
Karma: 159
Posts: 2927
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

You can't use a voltage divider to power a load, since the voltage out depends upon
the load current. IE, the usual formula for the v.div assumes no load current.

One solution is to use a voltage regulator, but something like 7.5V @ 2Amps is not easy to
produce. You should probably look for some kind of dc-dc converter that will push 2A
and where you can set the voltage out.
Logged

Offline Offline
Newbie
*
Karma: 1
Posts: 30
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I knew it!, I just knew it, just like that dream of winning the lottery, so real, so vivid, until I woke up smiley

I havn't gotten my starter kit yet and am going nuts  smiley-mr-green
« Last Edit: October 17, 2012, 11:14:52 pm by NobleNoob » Logged

Pages: [1]   Go Up
Jump to: