Here is a simple, yet useful circuit of an Arduino 4-digit 7-segment LED display unit. The module used here is a self-contained, compact common-cathode module containing four 7-segment LED numeric ...

For testing purpose only one 330 Ohm resistor (R2) is added between ground rail (0V) and the common cathode pins (3 & 8). It is better to directly connect pins 3 & 8 of the display to ground rail.

This seven segment art display makes use of a 81 seven segment red common cathode LED displays. The LEDs are arranged onto 100x100mm boards that each contain an Arduino Nano and 9 seven segment dis… ...

This ultra-cheap (under US$2), daisy-chainable, 16-channel, I2C-connected board with 12-bit PWM outputs will directly drive an individual LED (like one segment of the display) on each channel.