Author Topic: Voltage and Amps... (Read 2838 times)

Barry Barcrest · « **on:** October 25, 2007, 05:58:20 pm »

I want to run the lightening discs in my juke. They are 12volts 500ma, am i correct in assuming they can be run off a PC Power supply? As long as the volts match the amps are not a problem are they as i can't feed in too many amps can i?

DaOld Man · « **Reply #1 on:** October 25, 2007, 06:21:49 pm »

It should work just fine.
The current is what the device pulls.
Having a power supply that can "put out" more amps than the device needs, should be fine.
(As long as the power supply is voltage regulated and not current regulated. Most PC supplies are voltage regulated).
You should be fine.

Barry Barcrest · « **Reply #2 on:** October 25, 2007, 06:34:59 pm »

Cheers i just wanted it confirming. Thanks.

DaOld Man · « **Reply #3 on:** October 25, 2007, 06:37:53 pm »

Let me know how it works I will sleep better at night knowing I didnt give bad advice..

Can I ask what a lightening disc is?

ChadTower · « **Reply #4 on:** October 25, 2007, 06:46:47 pm »

You don't "feed" amps the device but you can draw too many amps from the power supply. Amperage is pulled, not pushed, in this situation.

Barry Barcrest · « **Reply #5 on:** October 25, 2007, 06:50:15 pm »

Quote from: DaOld Man on October 25, 2007, 06:37:53 pm

Let me know how it works I will sleep better at night knowing I didnt give bad advice..

Can I ask what a lightening disc is?

It is sound to light type thing that has lightening type effect on it that reacts to music, i'm not wiring up tonight.

DaOld Man · « **Reply #6 on:** October 25, 2007, 07:00:28 pm »

Good luck, and please posts some pics.
My next dream project ,after my rotating monitor and whatever else I get excited about

is a juke box, so the lightening discs sound very interesting.

Barry Barcrest · « **Reply #7 on:** October 25, 2007, 07:44:38 pm »

I also have a cool idea with some led strips... Don't worry pics will be posted. The lightening discs are the same as what McCoy has mounted in the bottom of his new jukebox project if you wanted to see what i was refering to.

See them here...
:nlp

DaOld Man · « **Reply #8 on:** October 25, 2007, 09:01:08 pm »

Hey I like those!
Where do you get em?
They might look cool on an arcade cab too.

Barry Barcrest · « **Reply #9 on:** October 25, 2007, 09:07:58 pm »

I'm not sure, i was given mine.

superbigjay · « **Reply #10 on:** October 25, 2007, 09:16:14 pm »

Quote from: DaOld Man on October 25, 2007, 06:21:49 pm

It should work just fine.
The current is what the device pulls.
Having a power supply that can "put out" more amps than the device needs, should be fine.
(As long as the power supply is voltage regulated and not current regulated. Most PC supplies are voltage regulated).
You should be fine.

Exactly what DaOldMan said.

In fact you NEED a power supply that can supply more than the total of amp pulled by all the device connected to it.
Exceeding the power supply limitation, would make it heat or the supplied voltage could drop below its spec.

Jay

Barry Barcrest · « **Reply #11 on:** October 25, 2007, 09:31:18 pm »

As it's only 500ma i am pretty sure my 300watt pc supply should be able to run them, i am only hooking up 2. I was also thinking of running the screen off it though as well and i'm not thinking that might draw too much power... Hmm.

superbigjay · « **Reply #12 on:** October 25, 2007, 09:58:47 pm »

as you said, you have enough power with your pc power supply...

Barry Barcrest · « **Reply #13 on:** October 25, 2007, 10:17:57 pm »

Yes but i don't think there will be enough juice to run the screen, i need to look at the amps on that. Anyone know how many amps you get off a 300watt pc power supply.

Avrus · « **Reply #14 on:** October 25, 2007, 11:01:04 pm »

Quote from: Barcrest on October 25, 2007, 10:17:57 pm

Yes but i don't think there will be enough juice to run the screen, i need to look at the amps on that. Anyone know how many amps you get off a 300watt pc power supply.

Even on cheap P/S's you'll get 20 amps on the 3.3v line, 22-25 amps on the 5v line and 14 - 16 amps on the 12v line.

I think he'll be fine for the lightning, I can't see him running the screen off it though if it's a CRT.

Wade · « **Reply #15 on:** October 25, 2007, 11:08:44 pm »

Quote from: Barcrest on October 25, 2007, 10:17:57 pm

Yes but i don't think there will be enough juice to run the screen, i need to look at the amps on that. Anyone know how many amps you get off a 300watt pc power supply.

A 300 watt power supply at 110 VAC from the wall is about 300/110 or 3 Amps. That's the absolute max it will output to all the devices connected to that power supply. In reality, the power supply could shut down with less load.

Most monitors seem to take about 1-2 amps at 110 VAC.

Whether it will work for your screen depends on how many volts the screen needs. Does it take a DC input? What's the voltage, 12VDC?

Wade

Neverending Project · « **Reply #16 on:** October 25, 2007, 11:38:14 pm »

Quote from: Avrus on October 25, 2007, 11:01:04 pm

Even on cheap P/S's you'll get 20 amps on the 3.3v line, 22-25 amps on the 5v line and 14 - 16 amps on the 12v line.

Are you sure about that? Vacuum cleaners don't even draw 20 amps. Besides, computers deal in miliamps, don't they?

Avrus · « **Reply #17 on:** October 25, 2007, 11:51:41 pm »

Quote from: Neverending Project on October 25, 2007, 11:38:14 pm

Quote from: Avrus on October 25, 2007, 11:01:04 pm
Even on cheap P/S's you'll get 20 amps on the 3.3v line, 22-25 amps on the 5v line and 14 - 16 amps on the 12v line.
Are you sure about that? Vacuum cleaners don't even draw 20 amps. Besides, computers deal in miliamps, don't they?

It's all about watts.

So on the 12v line you can do 192 watts or so. (12v * 16 amps) He only needs about 6 watts per light (12v * 0.5 amps) so he's golden.

Assuming a vacuum cleaner is 12 amp motor (and a good motor) pulling 110volts, that's 1,320 watts. Quite a bit bigger than the 192 above.

Barry Barcrest · « **Reply #18 on:** October 25, 2007, 11:52:41 pm »

The screen is 12volts DC yes, i figured there wouldn't be enough juice. I will have to use a power brick for that they, no big deal i suppose.

Oh yeah i'm on 230volts here BTW.

Avrus · « **Reply #19 on:** October 25, 2007, 11:56:14 pm »

Quote from: Barcrest on October 25, 2007, 11:52:41 pm

The screen is 12volts DC yes, i figured there wouldn't be enough juice. I will have to use a power brick for that they, no big deal i suppose.

Oh yeah i'm on 230volts here BTW.

230 volts? That sounds like devil talk!

Ed_McCarron · « **Reply #20 on:** October 26, 2007, 11:00:14 am »

Quote from: Wade on October 25, 2007, 11:08:44 pm

A 300 watt power supply at 110 VAC from the wall is about 300/110 or 3 Amps.

3A on the input side.

To simplify, look at straight AC:

A 120v -> 12v transformer (dividing by 10) drawing 3A on the 120v side is capable of supplying 30A (multiply by 10) on the 12v side.

Less core loss and such.


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