12v converted to 6volts. how to do?

lets say we have a mobile electronic product that uses 6volts from a cig lighter plug that id like to hardwire. im sure there is a resistor in the cig plug. how do i put a resistor inline to drop the volts?owner of

Motion Marine & Car Audio

the florida keys

What kinda current draw is the load device going to be drawing? This will need to be determined before selecting a resistor because if you just pick a resistor you may end up burning it up by using it over its power rating. Similar to the way speaker impedances work. If you have a 12V source, you will need a series resistor of the same value of the load (whatever you are powering). When you have a series circuit, the voltage across each load will add up to the input voltage. Thus, if you have 3 resistors in series with a 12V source, they will drop a total of 12V. If you have 2 resistors, of the same value, each will drop equal voltage, thus 6V each. Therefore, if you select a resistor with the same impedance as your load, you will be able to drop 6V across your load. WOW. ENOUGH SAID. I am working on a BS degree in Electrical Engineering. Actually working on designing a small 5-band EQ as a project for one of my classes this semister, how fun. Let me know if you have any other technical questions. For quickest response, e-mail me @ drvnbysound@aol.com

Let  us know the current your device will need.You might be able to use a resistor and a zenner diode for a regulator.Or use a NTE 962 or 1962 3 terminal regulator ic(simple).RussBigDog

a mechanic friend of mine has a kit that will test the draw of the unit and determine the size resistor. i thought this subject would be fairly simple, but its very complex. i was thinking i could just solder a resistor inline with the power wire. i undestand i must use the right size resitor to make sure i have enough and no too much power. what does a simple resistor look like? where does one but them? blah blah blah... owner of

Motion Marine & Car Audio

the florida keys

dudek38 wrote: a mechanic friend of mine has a kit that will test the draw of the unit and determine the size resistor.

 Measure the draw of the unit with an ammeter then use Ohm's Law.

 Item draws 150ma.. needs 6 volts..

 Resistance = volts divided by amps

?=6/.150

R= 40 ohms

 To find wattage of the resistor, multiply amps times voltage..

Watts = 6 volts * .150 amps

Watts =  0.9 - use a 1 watt resistor.

 Personally, I'd just use an adjustable voltage regulator.. It depends on what the device is, but using a voltage divider circuit with resistors usually isn't the best way in terms of voltage regulation..

 For parts, I use Digikey, Jameco, JDR Microdevices, and when I need something right now, Radio Shack. Unfortunately, Rat Shack will be the most expensive, and the people behind the counter won't have a clue about electronic components.

 Regards,

 Jim

You can't use a voltage divider, because the resistance needed will change with the load hooked up. Use a regulator.2009 Pontiac G8 in planning stage

HU: ?

Speakers: ?

Amps: ?

Yes, the regulator is the easiest way to do it. If you buy a three terminal fixed regulator, the most common being a 78xx with the xx being the desired fixed output voltage (and that's an industry standard number to cross reference) your installation is as simple and straight-forward as you can get. See the diagram below: You can order this device pretty much any place they sell electronics components - should run about 4 dollars. The best part of this type of installation, is you need to do NO figuring, no math, no construction... it is a simple point to point device, with regulation. This means that whether you car is running or off (14.4/2 = 7.7 volts or a 28.3% OVERVOLTAGE if you use a simple voltage divider - BAAAAAD) and no matter what the load is (up to the safe operating load of the device) you will ALWAYS get just exactly 6 volts... I would have thought a BS in Electronics would have known about simple three terminal fixed regulators... (jab - poke - jab) It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Order from www.mouser.com btw, and if you need more than 1.5A, you can well, find a regulator that does support more, or you can put regs in parallel for (Current each will take) * (Amount of regulators)2009 Pontiac G8 in planning stage

HU: ?

Speakers: ?

Amps: ?