Does a 7 segment display need only one resistor on the common pin?

Using Arduino Project Guidance
1

I've seen people using multiple resistors and people using one resistor on the common pin. I need to know witch one is better.

2

Well, with 7 segments on, and one resistor, the current is shared, usually not equally, between the 7 segments, whereas with only one segment on, that LED gets all the current. Perhaps, there will be noticable intensity differences?
So, for example, a 1 would appear quite differently than an 8.

3

Yes, each LED in the 7-segment display needs its own current limiting resistor.

4

Thanks

5

Each LED need's it's own resistor.

The resistor limits the current so if you have one LED on and then then you turn-on more LEDs the current gets split between the LEDs and they get dimmer.

6

What happens when you try? Is it a difficult experiment?

7

Unless of course you are multiplexing by segment instead of by digit. If multiplexing by segment, only one segment of each digit will be on at a time, so the common cathode resistor will limit the current to the same level for all segments.

1 Like
8

For shure, your are right.

9

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