Dell Mini 9 Hardware and Upgrades Discuss Dell Mini 9 Hardware and Upgrades.

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  (#1) Old
xokeman xokeman is offline
Posts: 52
Join Date: Apr 2009
Default Exploration in adding a REAL A/C POWER indicator - 05-22-2009, 08:03 AM

In the next couple weeks I will be researching adding a led to indicate that the power plug is indeed providing power. The only issue i see for now is dropping the 19v to a manageable 3v or so for my led i figured the use if a resistor to drop that voltage would be the ticket but I am not sure as to what size. This is the reason that I am posting here!! some might say "why would you want to do this when one can simply look at the battery to show that there is no power in the sys tray." but to those I say ... well what if your computer is turned off!! or the lid is closed???

Anyways this is what modding is all about. getting as many cool features added to your mini as you can possibly never use!!!

insights / failures / advice definitely welcome and even critics


I will post my finds from my multi-meter soon!!
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w-ham w-ham is offline
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Default 05-22-2009, 09:08 PM

Hi. I'm not sure I understand what you're trying to do. Are you trying to make something similar to what the Kill A Watt does?

Also the color of the LED will make a difference on what resistor you need to use.
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BoaZ2020 BoaZ2020 is offline
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Location: Philadelphia, PA
Default 05-22-2009, 09:49 PM

To calculate the value in ohms of a dropping resistor you solve the following formula...

Resistance (ohms) = ( Voltage Source (volts) - LED Voltage (volts) ) / Desired LED Current (amps)

So basically if you had a 19v supply, and the LED required 3v (probably less like 2.0v) and you wanted to provide the LED with a standard 20ma (milliamps) draw then the formula would look like this...

R = (19-3) / 0.020
R = 800 or 800 ohm resistor.

Please check the specifications of the particular LED you would like to use before just randomly assuming these values... Always err on the side of too high resistance, as this will not harm your LED.
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xokeman xokeman is offline
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Join Date: Apr 2009
Default 05-23-2009, 03:49 AM

thank you so much for your input I will be certain to update you when I add the light!
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