How do I lower the voltage from a DC power source without ramping the amps up?

Question

Specifically, I need to lower 12v DC current down to about 3v, and I need to do it without effecting the amperage. Any ideas on how I could do this?

Answer 1

In a DC circuit, the easiest way to reduce voltage is to add resistance in series with the load.  If the voltage is critical, a Wheatstone bridge type of circuit will also work.  Be careful that you don't confuse voltage and amperage.

Answer 2

The best way is with an active switching power supply.  These are switching regulators that require very few parts- the PWM IC, an inductor a few capacitors and resistors.  It is 95%+ efficient and will take in a large range of input voltages and give a nice, solid 3V.  Look in the back of any ECN or Electronic Design magazine for a company that makes them and gives circuits.

You don't make any sense saying "without effecting the amperage", besides the misuse of the word effecting, which should be affecting.

Answer 3

I don't understand "effecting the amperage" ? do you mean the current can't change?

When you reduce the voltage to a load, the current almost always is reduced also. Ohms law, I = E/R, current is proportional to voltage.

Or do you mean without changing the max current available? Clarity in questions is very important!

In this case, you can use a resistor or a rheostat.

Or a 3 terminal regulator.

Or a switching regulator.

Or a zener diode.

It all depends on how much current you want/have which choice you use.

Answer 4

Get an inverter with adjustable voltage.  Or correct transformer.