9 Volt Tap?
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Lol that's a bit excessive.
I'll just use a voltage regulator, or resistor setup if I have to, but I am trying to ask if there is anywhere on the truck that is already brought down to 9 volts?
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Negative, all current locations would be at 12V.
step down transformers only work with AC, not DC that is found in vehicles.
the voltage regulator you posted later is the way to go.
If the source is constant 12v (as in, voltage doesn't dip much under load) and you've got some diodes lying around, you can use them in lieu of a regulator. A silicon diode typically has a voltage drop somewhere around 0.7v. Put 4 of them in series and you're in business.
If you decide to use a regulator, something that looks like this will be cheaper and smaller than a switchmode DC/DC converter like the one q-ball posted.
If you decide to use a regulator, something that looks like this will be cheaper and smaller than a switchmode DC/DC converter like the one q-ball posted.
you will probably find something similar if you crack open just about any dc voltage supply. the switched one you plug in to a car will have a resistor on each switch position to control the output voltage.
I built a voltage supply with one of those in junior college. use a potentiometer to adjust the voltage.
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would give you 5v or less depending on the cell phone model. a DC to DC converter will do what the OP wants and cost <$20 at walmart.
This specific model appears to have been made with semiconductors, but you're right; it can be done with resistors. The problem with using resistors is that they are sensitive to variations in source voltage, whereas regulators are more forgiving. It makes little difference in most automotive applications, because you already know the input voltage and the load.
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Just what I was going to add.
Vehicles usually are not a true/stable 12v.
that semi conductor is a voltage reg. you use a resistor to set the voltage on the control/ground leg (see page 8/40 of the PDF) The ratio of the two resistors you use sets the ratio of output voltage to input voltage.
trying to do it purely with resistors will yield a different voltage depending on the load you put on the circuit.
The voltage regulator will change its resistance electrically so the voltage doesn't change based on load.
a lead acid cell is 2.1 volts. 6 cells in series is 12.6 volts. with the alternator running, your gonna be at a higher voltage so the battery will recharge. I believe it takes about 2.2 volts per cell to recharge a lead acid battery.
See if your camera supports above 9v.. Lots of the little mini surveillance cameras and video components, receivers, transmitters, hardwired cameras, etc.. that run on 9v batteries, always come with 12v AC/DC power supplies even though it says "9v" on the device it self. They may have their own regulators inside.
Ah I see what you're saying now: the resistor array is used to control the duty cycle of the regulator. I thought you were trying to say that the resistors did the work, so I tried to explain how that could be problematic under certain conditions, even with a constant load. My bad.
Depending on what type it is. The LDO regulator I posted can be likened to a resistor, but the device q-ball posted operates by opening and closing an electrical gate, so to speak.
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Good call. I'll have to check. I completely forgot about that.
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the alt puts out around the 14.4vDC its a range but thats the average for a charging system that is operating correctly.
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I looked at walmart a week or two ago and didn't see any DC to DC converters
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