stepping voltage down

I am looking to some how power an accessory that runs off of 9 volts DC in an vehicle that obviously runs on 12 volts. Basically I am trying to find out how to step the vehicles 12 volts down to 9 to run this accessory.

Would it just be as simple as adding a resistor on the positive wire?

you would nee a voltage regulator part # LM7809. this will give you the output you are looking for. there are 3 leads. voltage in(in this case 12 volts) ground, and voltage out 9 volts. what are you trying to power? this can supply about 1 amp.

jeffwhiteman wrote:

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this can supply about 1 amp.

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   That was the important part,  I just didn't want it to go unnoticed.  Depending on how much current you need, you can parallel several of these.  You may need to mount them on a heat sink of some sort.

It is a generic (FX-never heard of it...?) old school NES video game system. Customer picked it up off ebay, and dosen't want to invest in a power inverter. So I figured thier had to be a simpler alternative.

If it has a Wall Wart type power supply, it should tell you how much current the power supply is capable of producing.  It will be right next to where it says 9 volts.  It will probably be 500 or 750 Milliamps.  Or it could be as much as a couple of amps.  That is the number we are concerned with.

9v 300mA

If you go with a 7809 and our going to run more then ~100mA per 7809 you will need a heat sink for each 7809.

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Kevin Pierson