Do three leg LEDs have a polarity?

[Che_Guitarra]

Sorry if this question is so basic and might cause offence

I'm building a guitar pedal with a three leg LED in the kit - first time i've ever toyed with one.
Three-leg LED polarity - there's no labelling on the PCB to advise a correct polarity, not does the LED seem to have any orientation indicators, so I guess i'm safe. But I better ask, just to be sure.

 

[David Kulka]

All LED's (all diodes) have polarity. You can check polarity with a DVM that has a diode check function by trying the leads in each direction and seeing which way causes the LED to glow. Or just try in your circuit in both directions and see which way works. Or check the datasheet if you can find it.

 

[JohnRoberts]

The three leg LEDs I've used in the past had a common cathode for the center lead. Look for a data sheet describing the LED.

JR

 

[pucho812]

Yes they have polarity.
A 3 leg LED is usually a bicolor LED. It Will have 2 X anodes and 1 X cathode aka 2 X positive connections and 1 X negative connection.

Depending which + gets voltage will determine color. Center leg is usually cathode as JR said.

 

[Script]

Yes, common cathode or, and they also exist, common anode.

Easiest and fastest is to just try loosely in that circuit they go into before heating up solder.

 

[micolas]

Bi-color LED R,G
Tri-color LED R,G,Y (through simultaneous lighting, red and green are composed and yellow light results)