Testing individual segments of a 7 Segment display

Today I took one 7 segment display from my college lab. While I’ve used these before, I saw this after a long time. Now I was trying to remember how to operate it. The one that I got was common cathode type. So in this cathode is common. Now cathode is the negative terminal of 7 segment display and needs to be grounded. So logically if you want any segment to glow you need to supply Vcc. But 7 segment display is nothing more than a group of led’s arranged in specific order and of particular shape. So like any ordinary led’s it will definitely burn if the current exceeds the rated value. That is why we normally use current limiting resistors. But testing using that set up is tedious. So we’ll learn how to test the segments using a multimeter.

One more thing, the printed code on seven segment display will have a CC mark for common cathode and A for common anode.
7segLed

Above figure shows both the variants of 7 segment displays i.e the common anode and common cathode.

Steps involved in testing:

1) Keep the multimeter in diode mode.

2) Now depending upon which variant you have you’ll have to make connections.testing-diode-using-digital-multimeter

For common cathode place the negative probe of multimeter on the centre pin and then place the positive probe on the segment pin that you want to test.

For common anode place the positive probe of multimeter on the centre pin and then place the negative probe on the segment pin that you want to test.

Hope this tip will be useful.

Youtube link:

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7 thoughts on “Testing individual segments of a 7 Segment display

  1. At 3.20 you say thank you for watching this Video, but the viedo goes on without Sound. In fact you Need a better microphone. Your voice is not good to hear also in the other Videos.

      • It is also very important that you use the power of a Video to Show things you can not write down easily. A good Point is the part where you Show the difference of the common anode and cathode by simply using the multimeter and the red and black wire to Show the difference. If the video stands nearly still like in the Interrupt Video, it might be better to use Pictures and text.

      • The Audio in the seven Segment Video sounds better. than the one with the timer polling. If the Seven Segment Video is always the same as before it maybe the Speaker on my Monitor here is better than mine. Now the Label on the Displays side was also readable. That was not to read for me as i watched it before. But maybe that depends on the Monitor here.

  2. Pingback: Testing individual segments of a 7 Segment display » Hallo, here is Pane!

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