Posts Tagged: segment

Driving 4×7 LED with 4 resistors only (kinda Charlieplexing)

Traditional way of connecting 4 digits x 7segment display to microprocessor suggest using 4 transistors and 12 resistors: Would You be interested in shrinking everything down to LED display and 4 resistors ONLY ? Then continue reading. Assuming one LED segment (digit's stick) drives 20mA current this setup can take up to 160mA of power (7segments+dot)*20 if we will use multiplexing (turning just one digit at a time, then next, then next,... an doing it very very fast). Even this trick takes too much ... Read more