I am doing a project on Electriconics operated Traffic lights and in need of knowing a serial number of an LED that is supposed to work on 5v-DC?
Any Suggestion would be appreciated!


Muhammad89

Any LED will work on 5V, you just need to add an appropriately sized series resistor.

Originally Posted by Hero999

Any LED will work on 5V, you just need to add an appropriately sized series resistor.

Hi Hero999,


I thought of the use of a LED that was previously used upon a 12V-DC, but the light was little dim? what to do to make it fit the the %v-DC supply with full light, a resistor can be added if you suppose the applied voltage is greater than what it condones?



Muhammad89

Then the LED you bought obviously has a built-in series resistor.

You can get LEDs with built-in series resistors designed for 5V operation but it's cheaper to buy one without and add your own series resistor.

Originally Posted by Hero999

Then the LED you bought obviously has a built-in series resistor.

You can get LEDs with built-in series resistors designed for 5V operation but it's cheaper to buy one without and add your own series resistor.

Excuse me!
when I go to Electronics kit shops, they tell me they give you the LED based on the serial Number you request! most of them are shopkeepers and none of electronists!
In short, can i get a serial number that matches what I look for ?


Muhammad89

Originally Posted by Muhammad89

Excuse me!
when I go to Electronics kit shops, they tell me they give you the LED based on the serial Number you request! most of them are shopkeepers and none of electronists!
In short, can i get a serial number that matches what I look for ?


Muhammad89

hi.
Get the datasheet for the LED's that interest you.
The sheet will state the forward voltage drop of the LED and its operating current in milliamps.

To calculate the required series resistor do this sum:

[Vsupply- Vled]/Led current.

example: [12Vdc - 2V]/0.02 = 500R.

Using this simple formala you can calculate for any LED.