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LEDs are available in many different colors. As the current through the LED increases, the brightness also increases. Typically, the recommended current for an LED is 20 milliamperes (mA) or less. Above this value, the lifetime of the LED will be decreased significantly.
How do you adjust the brightness of LED lights?
To change the brightness by adjusting the resistor value – just add a potentiometer in series with the LED. When you adjust the knob of the resistor, the brightness of the LED will change. Another method is to turn the LED on and off fast. Maybe a few hundred times per second.
What happens when you change the brightness of an led?
Adjusting the voltage lower or higher will change the brightness, but only because it also changes the current- higher voltage means the current will increase in an LED. After ensuring that you have the correct voltage available to the LED, the next step is determining current.
How does the current of an led change with voltage?
Forward current vs forward voltage, notice how the current increases rapidly for a voltage above 3 Volt. Only 0.5 V more gives 4 x the current! This curve also changes between LEDs and over temperature. That is why it is better to feed LEDs with a current instead of a voltage.
What happens if there is too much current in a led?
If the voltage supplied to the LED is lower than required, very little current runs through the junction, resulting in low light and poor performance. On the other hand, if the voltage is too great, too much current flows to the LED and it can overheat and be severely damaged or fail completely (thermal runaway).
Why do LEDs have slightly different bias voltages?
Unfortunately no two LEDs are identical, they will all have very slightly different bias voltages which means that more current will flow through one than the other (it would be all the current through one if it wasn’t for the small increase in voltage as current increases that we normally ignore).