The 5mm Yellow LED is a standard light-emitting diode that produces yellow light when powered. It’s widely used in indicators, displays, and DIY electronics projects. 🔹 Key Features: LED Type: 5mm through-hole (T-1 3/4 package) Color: Yellow (~590 nm wavelength) Forward Voltage (Vf): ~2.0V – 2.2V Forward Current (If): ~20mA (recommended) Luminous Intensity: 1000–3000 mcd (depends on quality) Viewing Angle: ~25° – 45° Polarity: Long leg (Anode +) → Connect to positive via resistor Short leg (Cathode –) → Connect to ground 🔹 Working Principle: When a suitable voltage is applied across the LED, electrons recombine with holes, releasing energy in the form of yellow light. Needs a current-limiting resistor to prevent damage. 🔹 Example Resistor Calculation (for 5V Arduino): 𝑅 = 𝑉 𝑠 𝑢 𝑝 𝑝 𝑙 𝑦 − 𝑉 𝑓 𝐼 𝑓 = 5 𝑉 − 2 𝑉 0.02 𝐴 ≈ 150   Ω R= I f ​ V supply ​ −V f ​ ​ = 0.02A 5V−2V ​ ≈150 Ω ✅ Use a 150–220Ω resistor in series. 🔹 Applications: Status indicators on circuits. Traffic light models (yellow signal). DIY Arduino projects (blinking LEDs). Visual alerts in power supplies or chargers. Toys and small gadgets.