Jump to content
Electronics-Lab.com Community

Watt of LED


stonefox
 Share

Recommended Posts

You need the part number and detailed datasheet from the manufacturer of the LED to determine its continuous and pulsed absolute maximum allowed currents. The datasheet tells you the range of forward voltage or you can measure it. Then the power (Watts) is the current times the voltage.

Or you can try one at higher and higher currents until it fails or smokes then you can guess that the other LEDs are the same or better.

 

Most 5mm diameter LEDs have their voltage and brightness rated at 20mA. Their maximum continuous current might be 30mA or 40mA.

 

Link to comment
Share on other sites

An LED sets its own voltage. A red one is about 1.8V to about 2.0V. A blue or white one is about 3.2V to about 3.6V and they are all different unless they were all measured and grouped.

 

The brightness of an LED is controlled by adjusting its current, not its voltage. To avoid burning out an LED it must have a series current-limiting resistor. The series resistor and LED can be fed a variable voltage that adjusts the current which controls the brightness.

 

You said you have a transformer. A transformer has an AC output which might burn out an LED that needs a DC current. +15V at 5A will heat an LED with 15V x 5A= 75W which will instantly fry an LED designed for 2V x 20mA= 0.04W.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.