How to test a 7 segment display

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7 segment display is a display device to show the all decimal numbers as well as some English alphabet. It is used in digital clocks, digital meters, calculators and other electronic devices. There are two types of 7 segment display. Common anode and common cathode.
Here, I will show how to test a 7 segment display whether it is common anode or common cathode and working good or not. Actually, I am showing this using an analogue multimeter. If you wish to do it using a DC Source, compare the DC source with a multimeter when it is used as a DC Source. Let's see, how to do that.
Part List:
  1. An Analogue Multimeter or a DC source (Ex. 3V);
  2. 7 segment display;

Procedure:
  1. Set your multimeter for continuity test or set as a DC Source 
  2. Your 7 segment display has 10 pins. See at the right side;
  3. The pin 3 and 8 are internally shorted. Connect you multimeter positive/DC supply negative to any one of this two pin. And connect multimeter negative/DC supply positive with any rest of the pins.
  4. If any LED of your 7 segment glows make sure your 7 segment is common cathode.
If any LED of your 7 segment doesn't  glow, follow the steps below…
  1. Connect you multimeter negative/DC supply positive to any one of this two pin 3/8. And connect multimeter positive/DC supply negative with any rest of the pins.
  2. If any LED of your 7 segment glows make sure your 7 segment is common Anode.


*If any of the LED doesn't glow over the steps make sure that your 7 segment is not good one. 

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