FreeTrack Forum

Hi all


Today I have built my first clip. I have used 3 IR leds "TSUS 5400", a 39 Ohms resist and a cellphone recharger (4.9v)(serial assembly). To choose the resist I used the "led setup wizard", setting the forward  voltage of the leds to 1.5V and the led forward current 50 mA.

But now I'm looking the specs of the leds here :

http://www.datasheetcatalog.org/datasheet2/a/0s4cfts7uls54gietlirxr01lkpy.pdf

and I don't know clearly if I used the correct resist or I should have set foward voltage to 1.7 to make them as brighter as they can. I don't understand very well the specs as I can see two forward voltage (one in elect characteristics and the other type dedicated characterstics).

What is the correct foward voltage for them?

Thanks in advance

Darkgore

darkgore @ 09/04/2010 - 00h07 a dit:

Hi all


Today I have built my first clip. I have used 3 IR leds "TSUS 5400", a 39 Ohms resist and a cellphone recharger (4.9v)(serial assembly). To choose the resist I used the "led setup wizard", setting the forward  voltage of the leds to 1.5V and the led forward current 50 mA.

But now I'm looking the specs of the leds here :

http://www.datasheetcatalog.org/datasheet2/a/0s4cfts7uls54gietlirxr01lkpy.pdf

and I don't know clearly if I used the correct resist or I should have set foward voltage to 1.7 to make them as brighter as they can. I don't understand very well the specs as I can see two forward voltage (one in elect characteristics and the other type dedicated characterstics).

What is the correct foward voltage for them?

Thanks in advance

Darkgore

By specs it looks like your LEDs have 1.3V forward voltage, 100mA forward current.

Problem might be that "led setup wizard" assumes sources like power adapters provide +30%(!) of stated voltage and all calculations ran against V=6.4. You'd better check real voltage of your adapter with multimeter, and in  "led setup wizard" set it as regulated power source.

BTW according to "Radiant Intensity" diagram you'd better file LEDs flat to make light not so narrow focused. But don't destroy junction wire (thin yellow one on pic)