How can I convert 12V DC to 9V DC for a variety of currents <900mA?

Question

I was thinking of stacking 4 diodes in series for the 0.7V drop across each one, but that leaves me with 9.2V.

Ideas?

They have one what?

The current changes based on the audio being produced which shifts radically

Answer 1

Is your power coming from a 12 V Cig Lighter Socket? Does it have to be 900 Ma ? Could You settle for 800 Ma ? 12 Volts in, 1.5 to 9 Volts out.with 6 different Coax Plugs to Power most anything ! Go to www.allelectronics.com and check on the ACP-803 Converter. All of $6.75 .Good People. Good Products.Good Prices.Good Service.

Answer 2

You can use the silicon diode as you described. You can also use variety of 3 terminal regulators such as LM7809 (sold by various manufacturers) to step it down to 9 volts.

You could also use adjustable 3 terminal regulators such as LM317 to do the same thing.

With either of them, with a small heat sink, you can handle about 1 amp of current.

You can search the Internet for the exact schematic diagram. One thing I will tell you is that you will have to place a small tantalium capacitor very close to the regulators... otherwise, they can go into a violent oscillation and quickly overheat.

I am assuming you understand electronics.... if not, you can purchase a cigarett adapter with regulators built in that will do just what you described.

Answer 3

I actually like your idea of using diodes. Usually, a "9V DC" power input expects the voltage to be a little higher than 9.0V, so the 9.2V should be OK. Just make sure that you use diodes that are rated at 1W power, or more.

Answer 4

voltage regulator in a to3 or to5 case! Make sure you get one with adequate current ratings! Cost, all of a dollar!

Answer 5

just got o radi shack they have one from 3 volts to 12 just move the slider to the desired current and presto you have it

Answer 6

You can use a 7809 regulator IC.

Answer 7

http://www.uoguelph.ca/~antoon/circ/car912.htm

The above link might help...