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RSS >  Need help with resistor, Could not figure out the calculator
Circleplanes #1 19/08/2013 - 22h55

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Registered on : 19/08/2013

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Hello

I need help.
I am not confident in what I am doing. I want to build a 3 led cap.

The equipment I have are
3 SFH485P LED 1.5v forward voltage

4.9VDC Sony Ericsson power supply This is the one I have "CST-13"

I tried the calculator for a resistor value but it gave a calculation for parallel assembly.  I wish to connect them in series.

I have two resistors on hand and they are 4.7 Ohms 5%  and the other one is 2.9 Ohms 10%

Can I use either one of them?

Thank you so much.
Edited by Circleplanes on 19/08/2013 at 23h16.
moss #2 20/08/2013 - 04h15

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Registered on : 14/08/2013

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If the LEDs work with 50mA ( http://www.free-track.net/forum/index.php?showtopic=1856 )
The way to solve the circuit is this:
Posted Image
In your case you can use the two resistors in series, they will work as one resitor of 7.6 Ohms (4.7 + 2.9)
Good luck.
Circleplanes #3 20/08/2013 - 11h37

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Registered on : 19/08/2013

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That looks good thank you for the help. I will try it like that using two resistors

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