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12v Supply for PC screen


landroversforever
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Calling the electrical gurus on here....

Mate has given me an old PC screen to use in the truck. The screen takes a 12v input, but I don't know exactly how much its going to like the 12-14v it will get in the car.

How can I easily make it a steady 12v? I don't want to have an invertor or a 12v laptop supply as already have the power supply for the netbook (18v I think).

Thanks in advance :)

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The cheapest solution is to make your own! Determine how much current it requires. My Dell 17" screen says 1.9A @ 12v so yours is unlikely to be much more.

Buy a few 7812 Voltage regulators:

http://www.ebay.co.uk/itm/L78xx-Serie-Positive-Voltage-Regulator-IC-5V-9V-10V-12V-15V-18V-24V-/200714883555?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2ebb8a11e3

As pictured, the pin on the left goes to the vehicle 12v supply. Middle goes to Ground and the right one connects to the screen +ve. With a heat sink (a small 2" square of Aluminium is fine), each of these is good for up to 1 Amp. Parallel up two or more for higher current.

The smoothing capacitors are a good idea, but it will work OK without them as the screen will have it's own anyway.

An easy way to connect them if you don't have the facility to solder directly is to use the smallest size of connector blocks (Choc Blocks) you can find and screw one pin into each of three blocks then connect wires to the other side.

If you find the heat sink gets hot, increase the number of 7812's to increase the current handling capacity.

Most of the 5v lighter socket adapters you can buy for charging phones etc just have a 7805 (5v equivalent of the same thing) inside.

Si

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7812 will not really do the job, because of the drop.

I would use something like this http://www.ebay.co.uk/itm/150657732239?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

It will give you a stable voltage, no matter if the input is above or below 12v

I've used several of these from that supplier and can recommend

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I'm guessing you didn't buy this one! :blink:

Not sure how you can heatsink that one to get the full 3A since all the bits are surface mount.

Edit:- actually the only thing that other listing does give you is a view of the underside, which shows a plane with loads of vias under the power devices. So a bit of aluminium with heatsink compound against this surface might do the trick. (with suitable insulator!)

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