IR Led in series

rlowery98
Posts: 1
Joined: Wed May 25, 2011 2:17 pm

IR Led in series

Postby rlowery98 » Wed May 25, 2011 3:00 pm

i am building a IR project box with 10 ir leds in it i have them wired in series not parallel
i am using the 10mm Triple chips 200mW IR LED (a pack of 10)
how big of a battery would i need and how big of a resistor will i need to run the 10 led bulbs in my project box?
i have a 9volt battery connected to it now and each led has one volt going to it but it does not lite up
any help would be appreciated
thanks
robert

Tech_Marco
Posts: 4372
Joined: Mon Jun 15, 2009 3:00 pm

Re: IR Led in series

Postby Tech_Marco » Sat May 28, 2011 3:11 pm

The IR LED has 1.6V forwarded voltage so if you put 10 in series, it's potential drop would be 16V. There is no way for a 9V battery can light it up.

In your case, you may want to do 5 in series and add a current limited ressitor to avod over current.
The resistor could be 16~18 ohm. 1/4 watt

Then you put two set of LED/R in parallel and end up 10 LED in total. Current would be running about 200mA

For a 9V battery, it may ligh it up for 3hrs

Marco


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