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Help and information needed on a Resistor value

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Eralyn

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I wish to wire a super bright flashing 10mm LED to a circuit on my car, the battery supplies 12 volts the However I need to know what value of Resistor I need to enable me to do this. The specification for the led bought from Maplin is http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=35843&doy=13m3#spec

Super Bright Diffused Red 0.5V
Kingbright description: L-816BSRD-B
Forward voltage: 2.5V
Forward current max.: 55mA
Reverse voltage max.: 0.5V
Wavelength @ peak : 660nm
Power dissipation PT: 310mW
Light output min.@ 9V: 100mcd
Light output typ.@ 9V: 300mcd
Can any body please advise me as to the type of Resistor needed for this type of LED to enable me to connect to a circuit powered by a 12 volt car battery?
 
As you mentioned a circuit i would suggest you to use a regulator. Using simply a resistor may not be that efficient
 
Or may be a voltage divider followed by an appropriate zener... :confused:
Not sure.. Waiting for correction :)
 
keep it simple

Hello ...try to use a resistor 220 ohms 1 W..it will do it..calculated at max 13,8 V and abt 50mA......a 0.7 W will suffice because it's no continuos load...it's flashing....Good luck....Holger:)
 
All I want to do is wire the led to a 12 volt battery source without frying the led. so all Ineed is a resistor, but do not know the value of the resistor to use. I think the type of resistor i need is carbon film reistor.. the type that has coloured bands around.
 
Eralyn said:
All I want to do is wire the led to a 12 volt battery source without frying the led. so all Ineed is a resistor, but do not know the value of the resistor to use. I think the type of resistor i need is carbon film reistor.. the type that has coloured bands around.

As you buy from Maplins, look at this 2W range, use a 270R to allow for a vehicle charging voltage of 14.8v.

Resistor = (14.8v - 2.5v)/0.045A = 270R

If you can find a 1Watt version that would be OK.

**broken link removed**
 
ericgibbs said:
As you buy from Maplins, look at this 2W range, use a 270R to allow for a vehicle charging voltage of 14.8v.

Resistor = (14.8v - 2.5v)/0.045A = 270R

If you can find a 1Watt version that would be OK.

**broken link removed**
Thank you very much for your advice it is very much appreciated.
 
Eralyn said:
Thank you very much for your advice it is very much appreciated.

Hi,
Check the LED flasher datasheet, it operates from 3.5V thru 14V, suggests NO series resistor is required for a vehicle [12V] application.
 
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