Does anyone have schematic for converting 12V DC to 3V DC? Or know of a ready to use one?

Answer 1

If you know the load resistance of the device that requires the 3V potential difference, just place a resistor (R) in series with the 12V source and the load resistance (R_load). Choose R such that the voltage drop, V = IR = 9V

where I = 12V / (R + R_load)

You can do the algebraic simplification to find the actual value of R you need. You'll find that R = 3 * R_load

in summary:

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where one of the resistors is your device and the other resistor has three times the value of your device.

Answer 2

A zener diode may be used to reduce DC voltage. They are available in a number of power ranges and voltages, so the correct one must be selected for your application.

Zener diodes typically start at 3.3 volts, which may be too high for your application.

See also reference 1.

Answer 3

This is very easily accomplished with a voltage divider. The calculation is simple also, I tried to type the schematic into this but it F-ed up. Just look it up online. It's pretty simple.

Answer 4

You could use a step-down DC-to-DC converter, such as the MAX8723 from Maxim. See their website for datasheets and schematics.

Answer 5

Use a voltage regulator from Radio Shack. They have an input leg, an output leg, and a ground leg. You will probably find a 3.3v but most electronic devices have internal regulators to allow for a little over voltage.

Answer 6

Zener Diodes

Answer 7

It should be simple enough. Just remember to watch your ampherages to be sure that they don't come out too high for your application. When you decrease voltage, the amps go up unless you build a fix for it.

Cal-el