All About LEDs Created by Tyler Cooper Last updated on 2018-08-22 03:33:51 PM UTCGuide Contents Guide Contents 2 Overview 4 What is an LED 5 All the different sizes and colors 6 What are LEDs used for 9 Changing the brightness with resistors 12 Which LED is brightest (what is the resistor) 13 Which LED is dimmest (what is the resistor) 13 If we had an LED with a resistor that was 5K ohms, which LED would it be brighter than Which LED would it be dimmer than 13 Changing the brightness with voltage 13 Which LED is brightest (what is the voltage) 14 Which LED is dimmest (what is the voltage) 14 If we had an LED with a 1.0K resistor connected to a 4.2v supply, which LED would it be brighter than Which LED would it be dimmer than 14 Max brightness 14 We connect our LED to the resistor, as we turn it from infinite to to zero, what happens 14 We connect our LED through a 1K resistor, as we adjust the voltage from 0 volts to infinite volts, what happens What happened 1515 The LED datasheet 16 Forward Voltage and KVL 18 Quick Quiz 19 Let s say we have the same circuit above, except this time its a 5V battery and an LED with a forward voltage of 2.5V, how much voltage must be absorbed by the resistor 19 Let s say we have the same circuit above, except this time its a 5V battery and an LED with a forward voltage of 3.4V, how much voltage must be absorbed by the resistor 19 Ohm s Law 19 If I have a 3 ohm resistor (R) with a current of 0.5 Amperes (I) going through it. What is the voltage (V) across the resistor 19 Now I have a 1000 ohm resistor (R), and a voltage across it of 6.8V (V), what is the current (I) going through the resistor 19 Solving for the current 20 Revisiting Resistors 22 In the above breadboard, the voltage generator here is +5V, the forward voltage of the LEDs are 2.2V. What is the voltage across the 10,000 ohm resistor 22 Now that you know the voltage, how much current (I) is going through the 10,000 ohm resistor (R) 22 In the same breadboard, the voltage generator is +5V, the forward voltage is 2.2V, what is the voltage across the 1000 ohm resistor 22 Now that you know the voltage, how much current (I) is going through the 1,000 ohm resistor (R) 22 How much current (I) is going through the 100 ohm resistor (R) 22 Revisiting Volts 24 Lets start with the 9V-powered LED. The forward voltage of the LED is 2.2V, what is the voltage across the resistor 24 Now that you know the voltage, how much current (I) is going through the 1,000 ohm resistor (R) 24 Next, we will examine the 5V-powered LED. The forward voltage is 2.2V, what is the voltage across the resistor 24 Now that you know the voltage, how much current (I) is going through the 1,000 ohm resistor (R) 24 Finally, we will examine the 3.3V-powered LED. The forward voltage is 2.2V, what is the voltage across the Adafruit Industries