I have a sorted number of LEDs. How do I determine required voltage? Also are the voltages different for RED, GREEN, WHITE?

Thanks friends you guys are of enormous help!

Don

 

Each of your LEDs will have a foreward voltage drop (1.8V ~ 3.2V, aroud there). The LEDs have internal resistance, which forms that voltage drop across each individual LED. Being the case, I would suggest that you connect a 5V source in series with a 250Ω resistor and LED. Then, take a voltmeter and measure the voltage drop across each of your LEDs. Once you know that, you can calculate the full brilliance of light:

\(\frac{V_I_N - V_F}{I_F} = R\)

Where Vin = 5V
Vf = Foreward voltage you previously found out with a voltmeter.
R = Resistance you end up needing in that series circuit I mentioned.

Austin

 

Just the info I needed! Thanks Austin!

Don

 

Hello,

As you might know each color has its own voltage drop:

http://www.oksolar.com/led/led_color_chart.htm

This is a page from the EDUCYPEDIA link page on leds:

http://www.educypedia.be/electronics/composemiconductorsled.htm

For the exact voltage drop you will have to take a look in the datasheet of the led you are using.

Bertus

 

Have you read this?

LEDs, 555s, Flashers, and Light Chasers

I think chapters 1 and 2 will answer most of your questions about LEDs.