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LED string

colum

Jul 25, 2013
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Jul 25, 2013
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175
I have a mechanical arm that has 4 limit switches that is hooked up to 4 LEDs. 3 of the LEDs light up fine when activated but the last LED of the chain seems to take all of the power of the 9v battery when activated
I have switched LEDs etc but always the last Led prevents the first 3 from lighting
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
What value resistors do you have in series with the LEDs?
 

colum

Jul 25, 2013
175
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Thank you for responding Steve...One resistor at input + 330 ohms....colum
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
Let me guess, the last LED is red and the others aren't?

You should have a separate resistor for each LED.

Ok the basis of what you have now, four 1.2kΩ resistors should do the trick.
 

colum

Jul 25, 2013
175
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Jul 25, 2013
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175
Thanks Steve, I did try a Red a Green and a Blue
and thanks for the resistor placement and Ohm advice
colum
 
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