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 ...

One more suggestion: if we use an Arduino PWM pin as the common anode pin, we can power on/off the display and change its brightness. If we put in the sockets four 7-segments LED common cathode LCD ...