In a common cathode display, the com pin is connected to GND, and a positive voltage is applied to each segment (a-g) to illuminate it.Ī 7-segment display may appear to be a single display, but it is actually made up of seven independent LEDs housed in a single package, each of which requires its own current-limiting resistor to prevent damage to the LED segments. As the name implies, in common cathode displays, all of the cathodes (or negative terminals) of the segment LEDs are tied together, whereas in common anode displays, all of the anodes (or positive terminals) of the segment LEDs are tied together.
The difference is the polarity of the LEDs and the common terminal. The internal structure of both types is nearly identical.
There are two types of seven segment displays: common cathode (CC) and common anode (CA). Depending on the type of display, this pin must be connected to either GND (common cathode) or 5V (common anode). By lighting up individual segments, you can create any numeric character.ĬOM The pins 3 and 8 are connected internally to form a common pin. A, b, c, d, e, f, g, and DP are connected to the digital pins on an Arduino to operate the display’s individual segments.
