LED Diodes

Light Emitting Diodes

• semiconductor device that emits light when an electric current passes through it
• when current flows, electrons fill holes in semiconductor
• this causes the release of energy in form of photons

Flow

• Long leg = Anode (+)
• Short leg = Cathode (−)
• Cathode -> Anode

Voltages

| LED Color       | Typical Forward Voltage (Vf) |
|-----------------|------------------------------|
| Red             | 1.8 – 2.2 V                  |
| Orange          | 2.0 – 2.2 V                  |
| Yellow          | 2.0 – 2.4 V                  |
| Green (standard)| 2.0 – 3.3 V                  |
| Blue            | 3.0 – 3.5 V                  |
| White           | 3.0 – 3.5 V                  |
| UV (ultraviolet)| 3.0 – 4.0 V                  |