A 7-segment LED Display looks like the number “8” and has 8 parts that can light up to show numbers or characters. There’s also an extra part for a decimal point. You can make these parts light up by connecting them to your circuit using separate pins.
There are two types of wiring: common anode and common cathode. In a common anode, you connect all the positive pins together, and in a common cathode, you connect all the negative pins together.
Here’s a picture of how the pins are usually set up to help you see which pin connects to which part of the display. This way, you can make the right parts light up when you want them to.
To build a 4-digit display, we connect four 7-segment displays together, with each display showing one digit. To save pins, we use multiplexing, so the segment pins of each display are connected to the corresponding segments of the others. This allows us to control all four digits using fewer pins.
|Digit Height||0.56 in (14.22mm)|
|Color / Wavelength||Red / 457 ~ 467 forward forward|
|Forward Voltage||2.4 ~ 3.4 V|
|Luminous Intensity||85 ~ 185 mcd|
|3.3 V Supply||15 Ω Resistor|
|5 V Supply||100 Ω Resistor|
|12 V Supply||470 Ω Resistor|
|Continuous Forward Current||20 mA|
|Max Forward Current||60 mA|
- 1 x 7 Segment – 4 Digit