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10 led circuit help(white and red)

sage2605

Feb 9, 2013
12
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Feb 9, 2013
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Hi.i have a project that has 35 leds (in all) a mix of 16 red-10 white-9 rbg (i have a seperate post for RBG)..so to start the leds are red-2.0-2.2v 20ma..white-3.2-3.4v 20ma..what is the best way to power this many at once without a huge power supply.thank you
 

sage2605

Feb 9, 2013
12
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Feb 9, 2013
Messages
12
You have a total power requirement for all LEDs (including the RGB LEDs) of less than 4W. Even if you double that to accomodate resistor losses, you don't need anything more than a 10W wall wart. A 12V 1A or a 24V 500mA supply would be sufficient.

As to method:
https://www.electronicspoint.com/got-question-driving-leds-t256849.html

well some of the lights will not be on all the time. the white lights will come on when I flip a switch along with the others. what I have to make a different circuit to compensate for some of the lights not being on all of the time. reds and whites come on separately
 

sage2605

Feb 9, 2013
12
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Feb 9, 2013
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Can someone help me with rhe circuit.what resistors capacitors to use and such?
 

ICGengineerTech

Aug 15, 2012
58
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Aug 15, 2012
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58
I tried and...

I gave it a try and put in your numbers:

Source Voltage: 12
Diode forward voltage: 3
Diode forward current (mA): 20
Number of LEDs in your array: 10

What I got was a few options for arrays. I might not be understanding the whole problem here. Do you have to have each diode capable of turning on and off independently of each other?

~Bill
 

duke37

Jan 9, 2011
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Jan 9, 2011
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5,364
With 3V/led, three leds = 9V To get 20mA and a voltage drop of the extra 3V, a series resistor R = V/I = 3/0.02 = 150 ohm. The three leds should be connected in series with the resistor.
Three strings will allow nine leds and the current drain will be 3 * 20mA = 60mA

You can work out the resistor if you want to add the odd led.
 

sage2605

Feb 9, 2013
12
Joined
Feb 9, 2013
Messages
12
I gave it a try and put in your numbers:

Source Voltage: 12
Diode forward voltage: 3
Diode forward current (mA): 20
Number of LEDs in your array: 10

What I got was a few options for arrays. I might not be understanding the whole problem here. Do you have to have each diode capable of turning on and off independently of each other?

~Bill
all 10 white leds turn on together but I can cut that to 9 and just add the last one with its own resistor.the RGB leds (9) will all be on at the same time but different colors (no mixes,just basic RGB).The reds (16) will be on only when switched but all wil be on..thank you
 

sage2605

Feb 9, 2013
12
Joined
Feb 9, 2013
Messages
12
With 3V/led, three leds = 9V To get 20mA and a voltage drop of the extra 3V, a series resistor R = V/I = 3/0.02 = 150 ohm. The three leds should be connected in series with the resistor.
Three strings will allow nine leds and the current drain will be 3 * 20mA = 60mA

You can work out the resistor if you want to add the odd led.

Thankyou
 
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