I have a small electronic compass in my truck that runs off a 3 volt lithium battery. I want to hard wire it to the truck electrical system, but need to reduce the voltage to 3 volts. Not sure of exact current draw, but considering the battery last 6-12 months it must be very small.
Hi ,
You wants a linear regulator?
If Yes, you can use a variable IC coltage regulator like LM317, It is inexpensive and very easy to find, You can set teh voltage to 3 volts with 2 resistors.
Jose
As Jose said, you can use LM317 varaiable regulator, along with a heatsink, I don't think that the current will be more than 1A. If so then you can switch to DC DC converter.
In converting from 12V to 3V even with smaller current, you will face a heat problem. Simple calculation: (12-3)V*1A=9VA, you need a big heatsink for it. Use lm2574/75/76, simple , easy and robust DC-DC converter.
I think
If this equipment use a battery , the current must be very low, maybe lower than 20mA. in this case a linear regulator is enough, You must check what current you need to supply....
Jose
if u r unable to make LM regulator circuit then i will recommend u to use a car mobile charger giving almost 3.6V in standard and 3 to 5V are also there