Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: rackoon on February 14, 2006, 05:45:59 pm
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I bought a car equalizer/amp of eBay the other day and the instruction are brief to say the least when it comes to how many amps it draws. I'm trying to find a way to power this sucker and 100 UV LED's (about 3amps worth of juice). On another post someone recommend using a PC power source. This turned out to be a good idea for the LED's because the price for a small one on eBay is really cheap. Furthermore, it seems that I would have a lot of power left. I dont want to use my PC's power source in case somthing goes wrong.
For example, many of the PC power sources have 12amps worth of power going through their 12v line. Am I way off on this?
(So this is my question: Does 100 Watts draw roughly 1 amp?)
If this is the case than my 300watt amplifier would draw 3 amps and my LED's should draw roughly 3 amps. Does this sound right?
I wonder if the power surges caused by my amplifer will wreck my LED's. Maybe I should toss out my resisters that were made for 12v and use the 5v line coming off the power source and get new resisters.
Anybody have any thoughts on any of this?
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The math is a little off. :D
At 12volts and 300watts you are going to pull approx. 25 amps! You need a very big power supply for that. Amps = watts / volts acording to ohms law. Check out ohm's law here:
http://ourworld.compuserve.com/homepages/Bill_Bowden/ohmslaw.htm
I would not recommend that kind of power with 12v auto amplifer, I would look for some "home" unit you could use. Hope this helps you.
woody
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At 12volts and 300watts you are going to pull approx. 25 amps!
... that would be true IF:
1) the amplifier was 100% efficient and therefore 100% of its current draw went into the measurement of its power delivery (300W), which it is not. The amplifier most likely gets warm or even hot, indicating where some of your current draw goes.
2) the 300W was a good number - often inflated.
3) the amp was turned up to its maximum - current draw would then be at its maximum, in theory
... I used to work as a car stereo installer and the best way to know how much current this guy is supposed to draw is by looking at the rating on the fuse that is plugged into it.
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and now that I think about it - that would be a good way to protect whatever power supply you hook it up to. Find out how much current you have to spare on your 12V source, then get a fuse that is a bit smaller than that amount of amperage (current), and replace the one in the amp with the new one - so it protects your power supply. If it pops right away when you power up the amp, your amp is drawing too much current. But for the cost of the fuse, you have protected your power supply.
I would reccommend doing this on a separate power supply than the one running your motherboard and peripherals.