Multiple digit POV display - copy

418

03:12:21

I found a cool four digit seven segment display, but it only has 12 pins!  bit of googling revealed that the seven segments of all four digits are commoned together, and each digit has its own common cathode.  to make it useful, you have to use Persistence of Vision (POV) by cycling through the four numbers you wish to display and switching the cathodes on one at a time to show each of the four numbers, at a frequency higher than your eyes can detect.  simple! 

this example is not a real circuit; in reality the seven segment common cathode display has a real cathode on it.  see this page for a real example: http://m.instructables.com/id/4-Digit-7-Segment-LED-Display-Arduino/

published 6 years ago

hurz

6 years ago

Yes, this is done to limit the number of pin, and need a multiplexing to drive such segment arrays.

hurz

6 years ago

BTW, avaiolable in common cathode or common anode where you put a little transistor to swicth between the numbers. The multiplexing is not done on the 7 segment level a-g its done from the common connection.

hurz

6 years ago

unfortunately EC 7seg dieplays do not go that commnon cat or anode methode. Multiplexing is not possiblefrom the common side as it is hidden inside tzhe display

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