Question about a LED....

Hi I'm adding a LED to my Jamco Mini PSU device....

How do I wire my 12v LED????

Do I ground it off the 12v with a Resistor?????

Or Can I just run it in Line from the PSU to the +12 edge connector?????

Standard LEDs require a 2.0 to 2.6 volt supply at around 20 mA.
Connect the LED with cathode to ground and a 1 Kohm resistor in series to the 12 volt rail. There is an Ohms Law equation for working it out. R=(E-Vf) X 1000/I where R is the resistance,E is the DC supply voltage, I is the LED current in mA and Vf is the forward voltage drop of the LED,typ 2Volts. Using this equation the actual values are:
5 volts = 220 ohms
12 volts =560 ohms

so it should go like this?????:

+12-------Resistor-----Anode line----LED---Cathrode Line--Ground
|
|
-------Jamma Connector


Let me know if I got it right.......

Also I get confused.....

If I do a diode test my meter..... and I get a reading.... Is the wire that theGround probe touches the anode or cathrode wire????

norton9478 said:

so it should go like this?????:

+12-------Resistor-----Anode line----LED---Cathrode Line--Ground
|
|
-------Jamma Connector


Let me know if I got it right.......

Also I get confused.....

If I do a diode test my meter..... and I get a reading.... Is the wire that theGround probe touches the anode or cathrode wire????

Click to expand...

Yes you got it right.

With the black lead on the cathode you should get a reading on diode test.

The cathode is the shorter leg of the LED, also there is a flat on one side that indicates the cathode.

Thanks... THe LEd i bought is already wired.... SO otherwise I wouldn't know the cathode from the anode.....

norton9478 said:

Thanks... THe LEd i bought is already wired.... SO otherwise I wouldn't know the cathode from the anode.....

Click to expand...

No worries if you accidentally reverse the diode, it will just be reverse bias and will not illuminate. It will not damage the LED.