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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > Connection resistors 3 paralel or 1 is enough?

RSS >  Connection resistors 3 paralel or 1 is enough?
Sasha84 #1 09/04/2011 - 17h30

Class : Apprenti
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Registered on : 26/06/2008

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Previously i was using set as on the right image but now i am remodelling my set and just a thought "What if I would connect resistor as on the left image"
Its less messy but since this kind of connection is not mentioned here i guess it wouldn't work so the question would it work and if not, why not.
Posted Image
Battery:     2xAA
Resistors:   22 ohm
LED:          SFH485P
Edited by Sasha84 on 09/04/2011 at 17h31.
buccaneer #2 10/04/2011 - 08h02

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That should work, but resistance should be 3 times lower and power rating of resistor 3 times greater. In your case R= 7-8 Ohm P=1/2 W assuming you want to have ~80mA flowing through every LED
Sasha84 #3 10/04/2011 - 10h27

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Registered on : 26/06/2008

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A quick update i was browsing trough docs in freetrack/manuals folder and found there "doc_led.pdf" which is unfortunately entirely in french but i still found there a setup like i posted here which was (One rezistor 3 leds) it was surrounded by red border with big exclamation mark and i put it in google translate and this what it said.
ERROR NOT COMMIT:
This connection is bad because it offers no guarantee for the current
each LED. A small difference in the characteristics of a LED versus
the other may cause the passage of a strong current in one and a low current
in the other. This results in the best case of a difference in lighting
2 LEDs in the worst case by overheating of one of the LEDs and
possibly by destruction of 2 LEDs one after the other.
So yes an warning to others this is a no go.

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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > Connection resistors 3 paralel or 1 is enough?

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