over the past few months while i've slowly collected the parts i need for my projector, i've done alot of studying in these forums and elsewhere and i now know about everything essential to build a great projector, excluding one thing: POWER SUPPLY.
every post is "does this screen work?" "triplet this... ballast that. LCD...LCD...LCD" there seems to be a need for a discussion of power supply. for example, i have a sharp qa 1650, a dvd player stripped to be included as part of the box, and a lamp pulled from an overhead. i really don't want three seperate power cords running from the back. sure, i suppose i could just put a power strip inside the box with an unattractive hole in the back to run the cord out of, but i'm looking for something more user friendly/able to power on and off without opening the box. i don't know alot about amperes and wattage so could someone please explain to me the best way to run power to everything including a couple fans. i've considered a pc power supply but i really don't know what i'm doing on this one, so any advice would be extremely helpful.
every post is "does this screen work?" "triplet this... ballast that. LCD...LCD...LCD" there seems to be a need for a discussion of power supply. for example, i have a sharp qa 1650, a dvd player stripped to be included as part of the box, and a lamp pulled from an overhead. i really don't want three seperate power cords running from the back. sure, i suppose i could just put a power strip inside the box with an unattractive hole in the back to run the cord out of, but i'm looking for something more user friendly/able to power on and off without opening the box. i don't know alot about amperes and wattage so could someone please explain to me the best way to run power to everything including a couple fans. i've considered a pc power supply but i really don't know what i'm doing on this one, so any advice would be extremely helpful.
the panel is in transit. i just won an auction on ebay a few days ago and it hasn't arrived yet. as soon as it gets here i''l post what it says.
panel just arrived. the adapter says the output is dc12v 2.0a 24va. i assume 2.0 a is amps so 24va is 24 volts per amp. so, if my assumptions are correct, yes.
VA means volt amps (not volts per amp), which is just another way of saying watts. Basically the label is just providing you with redundant information, as you can find watts by multiplying volts by amperes. It's probably safe to assume that the 2 amp output on the AC adapter is a little more than the screen actually needs, and that most of the current draw in the screen comes from the backlight. If you have a multi-meter or just a current meter handy, you can measure the power draw on the screen when the backlight is disconnected.
The current draw from the fans can vary, but the packaging for them should say how much it uses (in mA). As an example lets assume that you have 2 12VDC fans that draw 200mA each (.2 amps), and that the screen draws .5 amps without the backlight. That adds up to .9 amps, which is well under 2 amps, meaning in this case you can use the single 12volt adapter to power everything. You will need to do a little wire splicing to do that (or soldering if you want to connect everything directly), but it shouldn't be anything complicated. For the DVD player, I suggest you keep it seperate from the screen and use it's own power supply (technically it would be best to keep the fans seperate too, but if there is enough "extra" current from the AC adapter then it shouldn't matter).
As for powering everything with only one cord going into the box, you don't need a power strip to do it. You can buy different lengths of power cords at most home improvement, then just splice everything together inside (with wire nuts). For plugging in the 12V adapter, it depends how it's made. If it has a length of cord between the actual transformer/converter and the plug that goes into the wall, then you can simply chop off the plug and connect the wires to the main power cord. If the plug is part of the transformer/converter housing (aka a wall wart adapter), then the easiest thing to do would be chop up an old extension cord for the plug (either way make sure you connect things with the correct polarity); you could also plug the DVD player into this. If you don't want the wires to be just floating around inside, and want something a little easier to connect/disconnect if needed, then you can use a screw terminal strip to connect everything together.
You will probably want to put a switch for each part (screen, fan, and light) between where it is connected to power and the actual supply. For the screen (if it doesnt already have a power switch you can use) and fans, it should be after the adapter and should switch the 12 volt line (as opposed to ground). For the light (assuming it or a ballast connects directly to the 120VAC line) it should switch the positive line.
The current draw from the fans can vary, but the packaging for them should say how much it uses (in mA). As an example lets assume that you have 2 12VDC fans that draw 200mA each (.2 amps), and that the screen draws .5 amps without the backlight. That adds up to .9 amps, which is well under 2 amps, meaning in this case you can use the single 12volt adapter to power everything. You will need to do a little wire splicing to do that (or soldering if you want to connect everything directly), but it shouldn't be anything complicated. For the DVD player, I suggest you keep it seperate from the screen and use it's own power supply (technically it would be best to keep the fans seperate too, but if there is enough "extra" current from the AC adapter then it shouldn't matter).
As for powering everything with only one cord going into the box, you don't need a power strip to do it. You can buy different lengths of power cords at most home improvement, then just splice everything together inside (with wire nuts). For plugging in the 12V adapter, it depends how it's made. If it has a length of cord between the actual transformer/converter and the plug that goes into the wall, then you can simply chop off the plug and connect the wires to the main power cord. If the plug is part of the transformer/converter housing (aka a wall wart adapter), then the easiest thing to do would be chop up an old extension cord for the plug (either way make sure you connect things with the correct polarity); you could also plug the DVD player into this. If you don't want the wires to be just floating around inside, and want something a little easier to connect/disconnect if needed, then you can use a screw terminal strip to connect everything together.
You will probably want to put a switch for each part (screen, fan, and light) between where it is connected to power and the actual supply. For the screen (if it doesnt already have a power switch you can use) and fans, it should be after the adapter and should switch the 12 volt line (as opposed to ground). For the light (assuming it or a ballast connects directly to the 120VAC line) it should switch the positive line.
thanks so much for the advice. however, it wasn't exactly what i wanted to hear. you see, the adapter is not a wallwart. there's a nice little port on the transformer that a power cord connects to that runs to the outlet. i was hoping to use this port instead of this guy.[br]https://secure.lumenlab.com/img/wiring/pem.jpg [br] found at lumenlab, but you're suggesting i cut this nice power cord up and use a completely different cord altogether.. so, i opened a heineken, took a long bath, and thought about it. you're absolutely right. i was trying to avoid spending the $24.99+s on the wiring kit at LL. this obstacle made me lose sight of the big picture. i can't run everything i want to on 2 amp 12vdc. i'll have to tap into 120v somehow. well i came across a guy with a few power entry modules and a couple power cords for cheap. i bought a terminal strip that, if i run the 120v to, should run the lcd, dvd player, and the lamp no problem. i think the power port pushes 10 amps so that should be plenty. so, i just want to say thanks for helping me realize that i need to be thrifty, not cheap. if any of this sounds "off" please let me know so i don't fry all my leghair off, but i think i got it. also, i have e few more of these entry ports since i bought in bulk, so, they're available if anyone wants one. i'm thinking $9. pretty cheap since that'll cover shipping, too. anyway, thanks again.https://secure.lumenlab.com/img/wiring/pem.jpg
the pem's, are they like the one's you pictured? and that's with the extension? how about a switch? let me know, thanks
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