IR Led

Other Hardware General Electronics
1

Hi. I just bought an IR Emitter rand Detector from Radioshack, RadioShack.com Official Site - America's Technology Store, and it says the emitter is 5V, but that doesn't make sense. I am just wondering what voltage it actually is. Has anyone used these?

Thanks.

2

RadioShack:
Cont. forward current: 150mA
Forward voltage: 1.3V typical, 1.7V max

These are the numbers you're looking for.

3

MAS3:

RadioShack:
Cont. forward current: 150mA
Forward voltage: 1.3V typical, 1.7V max

These are the numbers you're looking for.

I don't know enough about led's to know what that means, so Circuit Playground is telling me to use a 24 2/3 ohm resistor. It would probably be able to run without a resistor then.

4

Heh, nope. Down an IR led.

5

So the magic smoke escaped..
Sorry to hear that.

Your calculations seem to be correct, but it is an assumption that to dismiss the resistor is a good idea because your calculation results in a low value.
And you now know the danger of assumptions.
Next time always use at least the next higher available value resistor.
In this case that would be 27 Ohms.
Next after that would be 33 Ohms.
You can do some calculations to see what current would flow with those values, they'll probably be both good.

150 mA can't be controlled by an Arduino directly, so you must use a transistor for that.

6

MAS3:
And you now know the danger of assumptions.
Next time always use at least the next higher available value resistor.

Yep. I'll remember this for next time.