> Resistor Help., need help with Resistors.
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MRFOX |
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Class : Apprenti
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Registered on : 01/12/2008
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Ok so I am new to all of this. so I'm trying to put together a 3 led system.
I got 3 1.2v 5mm infrared LED's - which was all I could find at Radioshack.
and I did some calculations for resistors on the site. and this is what I got.
-for a 9v battery I need a 54 or 56ohm 5% resistor. 1 for all 3 LED's.
-for 2AA batteries, I need 8 or 8.2ohm 5% resistor. 1 for every LED.
so I went to frys. and found, 8.2ohm 5% resistors(1/4w). and I found some 56ohm 2% resistors(1/8w).
so my question is, the difference between 2% and 5%? is the 8.2ohm fine for this setup? or will the 56ohm 2% work?
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patio87 |
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Are you sure 8 ohms. I have the same LED's and when I do the calculator it tells me 18 ohms. That is for 2 batteries(3 voltls voltage value), forward voltage 1.2, forward current 100. It tells me 18 ohms resitors. Or is it telling me that the entire circuit should hae only 18 ohms? I'm under the impression that it mean that it calls for 3 18 ohm resistors.
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MRFOX |
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I'm not sure. I keep getting 8/8.2 ohms 5%. I'm calculating the 2AA as (1,2v) each. giving me (2,4v) but if I put (1.2) like you did, instead of (1,2) which is what is on the battery. then I get 18ohms. but would that be right? is the rig working for you?
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patio87 |
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Ok, see what I do for voltage value is 3, not 1.5(single AA battery). I'm not sure which they are asking for.
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MRFOX |
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I found that the thing is. I'm using rechargable batteries. which are (1,2v) and you must have a regular 2AA which is (1.5) so you should be right... I just hope I am as well.
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MRFOX |
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Seems to be working fine for me now. 3 - IR LED - 1.2V with 3 - 8.2ohms resistor. 2AA ( rechargeable Duracell ) 1,2v each. only problem is angle. need to figure out how to make the light angle wider. loose the light when I turn my head.
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didja |
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Hi MrFox,
Have a peak to the FAQ, you might get some of your question answered 
http://forum.free-track.net/index.php?showtopic=413
Here is an extract that you should find interesting :
The LEDs fade away when I turn my head only a small amount.
The viewing angle of your LEDs is too small, increase the viewing angle by filing the LED lens tips down flat, almost to the metal part and then make the final finish transparent matte (not too shiny, not too rough). Alternatively you can buy wide angle IR LEDs like SFH485P or equivalent (+/-40 degrees half angle). These LEDs are unlikely to be available from consumer electronics shops, instead try major distributors like Farnell and RS Components or through a specialist like LumiTronix.
Rémy  |
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MRFOX |
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Class : Apprenti
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didja @ 02/12/2008 - 19h28 a dit: Hi MrFox,
Have a peak to the FAQ, you might get some of your question answered
http://forum.free-track.net/index.php?showtopic=413
Here is an extract that you should find interesting :
The LEDs fade away when I turn my head only a small amount.
The viewing angle of your LEDs is too small, increase the viewing angle by filing the LED lens tips down flat, almost to the metal part and then make the final finish transparent matte (not too shiny, not too rough). Alternatively you can buy wide angle IR LEDs like SFH485P or equivalent (+/-40 degrees half angle). These LEDs are unlikely to be available from consumer electronics shops, instead try major distributors like Farnell and RS Components or through a specialist like LumiTronix.
Rémy
thanks. this will help. lots of helpful stuff there. thanks!
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didja |
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There also the hardware FAQ in the... hardware forum
Good readings
Rémy  |
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MRFOX |
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Class : Apprenti
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Got it working wonderfully!  , Finally IL2 feels like the game I always wanted it to be! AMAZING! |
