What do you do with 144 7-segment displays? If you’re [Frugha] you put them all together to create an epic clock. Each display has 8 individual LEDs — 7 segments, and a decimal point. P… ...

Available in 3, 4, or 5-digit varieties, these multiplexed 7-segment displays provided countless hours of entertainment to those who would spell upside-down words on their pocket calculators.

This 4 -digit 7-segment display section is wired around four common-cathode 7-segment LED displays, and four BC547 npn transistors. The 1K resistors are used for base current limiting, and the 390R ...