[MOVED] LED constant brightness

shubhangiagarwal · Sep 12, 2012

an LED with maximum and minimum voltage drop of 1.8V and 3v respectively should be connected to which of the following to get constant brightness:
(a) 29V supply with 820ohm
(b)5V supply with 120 ohm

betwixt · Sep 12, 2012

Trick question?

The brightness will always be constant if the voltage and series resistance are also constant.

Brian.

jeffrey samuel · Sep 14, 2012

as long as the supply is capable of dissipating power equal to the rating of the LED it will have constant brightness

HTA · Sep 14, 2012

In this case it is the better to use a constant current, or driving it like a laser diode with monitor diode(would mean you need a photo transtistor for the feedback). This provides optical power control. Here are the LD principles: https://www.ichaus.biz/upload/pdf/EuroPhotonics_H89_2004_Driving_Diode_Lasers.pdf.

Enjoy your design work!

[MOVED] LED constant brightness

shubhangiagarwal

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betwixt

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jeffrey samuel

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HTA

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[MOVED] LED constant brightness

shubhangiagarwal

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betwixt

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HTA

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