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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > LED Assembly Wizard??
Niek | #1 25/03/2008 - 01h17 |
Class : Apprenti Off line |
Hi!
I'm ordering some parts to build me a 3-point clip with SFH485P's. They need 1,5V and 100mA. I will power them with USB (with a PTC-fuse, 0,2A trip), so output is 5V. The leds are in series so when I want to calculate the resistor I get: 5V - 3x 1,5V = 0,5V over resistor. R=U/I => 0,5V/0,1A = 5 Ohm resistor When I calculate the same with the LED assembly wizard on this website it says I need a 20 Ohm resistor! What's going on?
Edited by Niek on 25/03/2008 at 01h31.
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larockonoli | #2 25/03/2008 - 05h26 |
Class : Apprenti Off line |
let me know if you get your setup running... I am thinking about running off a USB as well, but I have no clue on the fuse size, etc. so I would rather make sure someone has success on it first.
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tristan68 | #3 25/03/2008 - 11h16 |
Off line |
Hello Niek
I just checked the wizard. For your settings : - 5v USB power - 3 x SFH485P - 1.5v led voltage drop - 100 mA the wizard suggests the following, which IMO is OK : Can you please confirm the values you entered ?? BTW : - The wizard doesn't take account of the PTC voltage drop. You have to see for that. Next version will implement it. - You shouldn't power your SFH485P's at 100mA, it's the max value when led is PCB mounted. For cable mount, the max suggested value is about 75mA. Cya |
George | #4 25/03/2008 - 12h27 |
Class : Apprenti Off line |
Hi Niek,
you typed 1,5 instead 1.5 I made the same before... |
Niek | #5 25/03/2008 - 18h38 |
Class : Apprenti Off line |
Haha, that's it! And thanks for the tip about the 75 mA and PTC voltage drop! I'll check it out! I already ordered some female mini usb connectors to connect the usb cable to my future device.
Edited by Niek on 25/03/2008 at 18h41.
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tristan68 | #6 26/03/2008 - 19h54 |
Off line |
Hello niek.
NP , and good luck for your setup cya |
Syquus | #7 19/01/2009 - 16h42 |
Class : Apprenti Off line |
Does the LED Assembly Wizard online work? I'm trying to use it, filling with my info, but it doesn't give any responses. Tried with FF and IE
Regards |
Syquus | #8 19/01/2009 - 17h13 |
Class : Apprenti Off line |
I'm sorry for my last posts. It's working perfectly. I was introducing wrong values. (out of range for programmed webpage)
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kookookalvy | #9 23/01/2009 - 18h53 |
Class : Apprenti Off line |
Hey, I've never responded on a forum before. I used a 33ohm resistor for mine (and my buddies) You are trying to cut down output amps from 100mA to about 20mA I think, Mine ends up at 45mA with calculator thing. No problems with the USB, (so far) I guess if it were gonna fry my Motherboard it would have already. (I hope) I tried to donate too, but what a pain. |
tristan68 | #10 23/01/2009 - 23h06 |
Off line |
Hello kookookalvy
can you tell me what params you used ? thanks. cya |
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