LED with Diode?

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Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=12757
Printed Date: May 29, 2024 at 12:41 AM

Topic: LED with Diode?

Posted By: adamd_1
Subject: LED with Diode?
Date Posted: April 25, 2003 at 10:00 PM

Maybe its a silly question, but I have no knowledge with electrical terms. I just purchased a 12volt LED lamp for the dash, the packing indicates as follows: [12 volts, Yellow wire to cathode] There are 2 wires coming out of the LED one is RED & the other YELLOW. Can someone explaine what they mean by this?

Thank you:

Justin

Replies:

Posted By: BumpNGlow
Date Posted: April 25, 2003 at 11:23 PM

maybe it would help us out to know the brand or something? cuz I'm with you -- I'm confused.

Posted By: hotrodelectric
Date Posted: April 26, 2003 at 12:27 AM

A cathode is basically the gate in a diode or LED that allows current flow in one direction only. That yellow wire will go to ground. The simplest test is put that yellow to ground and the red to positive- it'll light up. Swap the leads, and you get no light. That's because the cathode is preventing the flow of electrons necessary to complete the circuit. Now, you need to be aware- not all,in fact most LED's cannot do this unless you have a resistor in line on the anode (power) side. Your LED in question is already a 12V, so you don't need to worry about that here. And don't ever worry about stupid questions, guys- they're one hell of a lot easier to fix than stupid mistakes.

Posted By: adamd_1
Date Posted: April 26, 2003 at 2:31 AM

Its a 12volt RED LED LAMP part # 276-011 from RadioShack chk it out at at their site www.radioshack.com