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How I can differe between common cathode 7-segment & common anode 7-segment

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abdu-abdu

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Hello there :
when I payed a 7-segmant display it wasn't work cus it was comman anode and it works only with negative voltage

I wanna know how to test the 7-segmant to know if it's common cathode or common anode

thank you
 
You can also use a digital multimeter's "DIODE" test function to light the LEDs of the 7-segment. If the positive lead is connected to the common and the LEDs light, it's common anode, otherwise it's common cathode.

You also won't need a series resistor with a multimeter, although the "DIODE" test function on the multimeter will only cause the LEDs to glow faintly.
 
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Most LEDs will not light from only 1.5V. A red LED needs about 1.7V to 2.2V and a blue or white LED needs about 3.5V.
 
You can do it using a 9v battery and a 1k resistor, try various connections, after a while you'll find out which is common and whether its a anode or cathode, and you'll also find out whicgh segment is which.
I've done this many times with displays from my scrap box, and ones got on the cheap from surplus stores and ebay.
 
hy can sme 1 hlp me hw to ...
We speak English here.
Is this the language of little kids? Then many vowels are missing.
"Hi, can someone help me how to ..." is what you should have written.
 
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