USB LED (GREEN)

 

This is a simple instruckable.

U will need:

LED Assembly

Male USB

Tape

Step 1

The resistor

Comments

[sparky96js]

thank u finally someone understands

[schkip1973]

you are correct. there is no current limiting in this circuit except for on the computer (USB limit). Don't expect the LED to last long.

[severepb]

why wouldnt the led last long? those particular leds(with the built in holder and resistor) are designed to run on 12-14v, due to the resistor. a usb drive port only runs 5v, which is less than half of what the led is designed for, therefore the led should actually last longer than usual

[schkip1973]

hey,

with a resistor in the LED housing it should be fine, as you have shown below in the pic. There is no mention of the resistor in the instructible, however, so someone 'off the street' making your instructible could easily buy just the green LED itself with no current limit resistor.
Hopefully they will see the thread and realise that they need either a series resistor to limit the current or the LED in housing like you have below.

Cheers
S

[severepb]

okay i see what you mean. i knew there was a resistor built into that led piece because i recently bought one, but i didnt consider being on the other side as a beginner in electronics who dont know that much about this subject.

but this led setup itself will still last

[parkerreno]

I really hope this doesn't sound rude, but if your LED is say about 3v (about average) and USB is supplying 5v, there is risk of burning out the LED, wouldn't a resistor be a good idea here?

[sparky96js]

It's hard to see but it is an LED assembly, there is a resistor in the housing.

[parkerreno]

(I'm only 13, but there could also be a small risk of damaging your computer, my electronics skills aren't amazing, but they are enough!)

[westernguy]

with an 3 volt led on usb and a 68 or 680 ohm resistor (hard to tell what the 3rd band is on the resistor) that limits the current to either 3 or 30 mA, a USB bus can supply at least 100mA, so you should be safe as long as you don't short the wires out accidentally. if you have a meter with continuity test check all the pins on the usb plug before plugging in