USB LED's

[33L]

Im wondering how to wire up to 8 led's off usb power and a have a few questions!


1. Could i run 8 of 1 usb lead or do i have to split it to multiple usb leads.!?
2. what resistors will i need for 3mm blue LEDs (yes i know its blue no flaming)
3. assuming i can run multiple led's of 1 USB anyone have a wiring diagram for this little mod!

If all goes well i will post pictures of my mod!

 

[Gaverick]

USB provides 5V, so running 8 LED's in a parallel circuit would provide 5V to each one, and when used with the appropriate resistor you can supply the required 3.3V to each one from one USB lead. The current from USB is 100mA, so 12.5mA will be enough to light up a LED.

For the leds
R = V/I = 5V / 0.0125A = 400 ohms so i would use 400 ohm resistor

 

[33L]

thanks for that! now i have a shopping lsit for the weekend - if the missus hasnt spent al lthem money by then!