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How to detect seven-segment digital tube

Is the seven-segment digital tube broken? Easily detect with a single multimeter

Q&A

 
How to detect seven-segment digital tube?
 
When testing a seven-segment digital tube, you only need one multimeter to do it easily. The following test steps may help you detect a seven-segment digital tube.
 
1. Take out the seven-segment digital tube and identify 1 foot first.
2. Now pick up the multimeter to set it up (use the red test lead into the jack labeled "+" and the black pen into the jack labeled "-".) - Set the multimeter within the continuity range.
3. Hit the buzzer file and test the multimeter (when in the buzzer file, the red and black pens are shorted and will make a sound). When the multimeter battery is low, the correct data will not be displayed. At this time, a new battery needs to be replaced.
4. Put the black pen on the multimeter on the 3rd or 8th. Generally, the two legs are connected inside.
5. Then place the multimeter's red pen on any other pin, such as 1 or 5 feet.
6. If any period of illumination, this seven-segment digital tube is a common cathode.
7. If there is no luminescence, swap the position of the test pen to test the anode and cathode.
8. Place the multimeter's red pen on the 3rd or 8th.
9. Now place the black pen on the multimeter on the remaining pins. If any one of the lights is on, it means that the seven-segment digital tube is a common anode.
10. Please check that all pins of the seven-segment digital tube are common cathode or common anode to ensure the normal operation of the display.
11. If some segments do not shine, then the seven-segment digital tube is bad.
 

Let's share a test example of a seven-segment digital tube.

 
The following digital tube is 67-1469-ND. Some people think that the A and F segments of the digital tube number 1 have problems. To do this test, you need to determine two points: First, make sure that the digital tube is a common cathode or a common anode; the second is to confirm which two pins activate

the A and F segments.
 
 











 
According to the data sheet, both pins are in the lower right corner. This is a common anode digital tube. The anode pin of digital tube number 1 is 14, the cathode pin of segment A is 16, and the cathode pin of segment F is 18.
 
 








 
 









 

 
 













 
Knowing the structure of the digital tube, you can adjust the multimeter to the diode file to detect it. Put the red test pen on the 14th foot and the black test pen on the 16th and 18th feet. You can see that both segments work fine. With this knowledge you can help you identify problems in your circuit.