Seven Segment Display Circuit (SSD) is a small device which show numbers easily.
It have 7 LEDs shape like 8.
Show numbers 0 to 9 and some letters.
It is used in clocks, calculators and electronic tools.
Two types are Common Cathode (CC) and Common Anode (CA).
We should know the difference which will help to connect with Arduino, microcontroller and circuits.
This article shows pinout, datasheet, working, making and formula for SSD.
Diagram with Pinouts:
Pin Configuration:
Seven Segment Display mostly have 10 pins and one pin is common.
Below table show pin setup:
| Pin | Segment | Function |
|---|---|---|
| 1 | E | Controls segment ‘E’ |
| 2 | D | Controls segment ‘D’ |
| 3 | Common | Common Cathode/Anode |
| 4 | C | Controls segment ‘C’ |
| 5 | DP | Controls the decimal point (optional) |
| 6 | B | Controls segment ‘B’ |
| 7 | A | Controls segment ‘A’ |
| 8 | Common | Common Cathode/Anode |
| 9 | F | Controls segment ‘F’ |
| 10 | G | Controls segment ‘G’ |
Common pin go to ground in Common Cathode and go to positive voltage in Common Anode.
Common Cathode (CC) vs Common Anode (CA)
Common Cathode (CC):
- All cathodes join together and go to ground.
- To turn ON segment it gives HIGH to anode.
- It is used when HIGH (1) turns ON the light.
Common Anode (CA):
- All anodes join together and go to +Vcc.
- To turn ON segment it gives LOW to cathode.
- It is used when LOW (0) turns ON the light.
Difference Table:
| Feature | Common Cathode | Common Anode |
| Common Pin Connection | Ground (0V) | +Vcc (5V, 12V, etc.) |
| Logic for Segment ON | HIGH (1) | LOW (0) |
| Preferred in | Microcontroller-based projects | Digital Circuits |
Datasheet Overview:
- Forward Voltage: 1.8V to 2.2V per LED
- Current: 10mA to 20mA per segment
- Power Loss: Depends on how many segments are ON
- View Angle: Around 30° to 60°
How It Works:
- Each segment has a small LED.
- It turn ON some segments to show numbers.
- Example to show 8 it light up all 7 segments from A to G)
- Example it show numbers on Common Cathode SSD.
Decimal Digit Representation (CC):
| Digit | A | B | C | D | E | F | G |
| 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
| 2 | 1 | 1 | 0 | 1 | 1 | 0 | 1 |
| 3 | 1 | 1 | 1 | 1 | 0 | 0 | 1 |
| 4 | 0 | 1 | 1 | 0 | 0 | 1 | 1 |
| 5 | 1 | 0 | 1 | 1 | 0 | 1 | 1 |
| 6 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| 7 | 1 | 1 | 1 | 0 | 0 | 0 | 0 |
| 8 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 9 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
For Common Anode the logic is opposite and gives 0 (LOW) to turn ON the segment.
How to Build:
Seven Segment Display Circuit (SSD) made up of:
- Outer body is made of plastic or epoxy
- LEDs are 7 small in 8 shape
- Wiring is of common cathode or anode inside
- Metal Pins are used to connect with circuits
Formulas and Calculations:
To keep SSD safe use right resistor with each LED.
Use Ohms Law to the find resistor:
Formula:
R = (Supply Voltage – LED Forward Voltage) / Desired Current
Example:
Supply = 5V, LED drop = 2V, Current = 10mA
R = (5V – 2V) / 0.01A = 300Ω
330Ω is common choice.
Conclusion:
Seven Segment Display Circuit (SSD) show numbers in many devices.
Know how they work like Common Cathode (CC) and Common Anode (CA) which help to connect right.
OLED/LCD are new but SSD are cheap, simple and work well.
With right resistors and logic SSD works with Arduino, Raspberry Pi and other microcontrollers.
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