The 7-Segment BCD Display (0.5″ Common Cathode) is a digital numeric display used to show digits 0–9 (and some letters) in calculators, clocks, counters, meters, and Arduino projects. The “0.5″” refers to the digit height (about half an inch), and common cathode means all LED segments share a common ground (–). 🔹 How it Works: The display has 7 LED segments (labeled a–g) and often a decimal point (dp). In a common cathode type: All cathodes (negative terminals) are tied together to GND. Each segment lights up when you apply +V (logic HIGH) to its pin. By combining segments, you can display numbers (0–9) and some letters (A, b, C, d, E, F). 🔹 Pinout (Typical Common Cathode 7-Segment): a, b, c, d, e, f, g → Control each LED segment dp → Decimal point CC (2 pins) → Common Cathode (connected to GND) 🔹 Electrical Specs: Forward Voltage per segment: ~2V (Red LED type) Current per segment: ~10–20 mA Logic: Apply HIGH (via resistor 220Ω–330Ω) to turn ON a segment 🔹 Applications: Digital clocks Electronic meters Counters and timers Arduino number displays Scoreboards 🔹 Example: Displaying “3” Segments a, b, c, d, g → ON Segments e, f → OFF