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This is a 1-digit 56.80 mm 7-segment display. I don't know if it's common anode or common cathode. I got this because that was the only available option at that moment.

This is the description of the product on the site:

enter image description here

Front view of the 7-segment display:

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Back view of the 7-segment display:

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It says "PA6" on the top left, "10" on the top right, "WLG 023011A/B(D)" on the bottom, in case it is not readable.

I would like to know which pin is common, and which pins are segment pins.

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    \$\begingroup\$ If you got this from a “good” seller then they will have the datasheet. \$\endgroup\$
    – Solar Mike
    Aug 25, 2023 at 8:48
  • \$\begingroup\$ What happened when you tried to find out using a multi-meter in diode or short test mode? \$\endgroup\$
    – Lundin
    Aug 25, 2023 at 10:10

2 Answers 2

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Chances are a 57mm digit has a number of LEDs in series for each segment (and a fewer number for the DP). Depending on the type of red die used, it might need Vf= 6.5 to 7.5V for four LEDs (and proportionally different if a different number of LEDs is used). So you might need a 9V or 12V supply. Almost certainly 5V is insufficient.

The decimal point might have two LEDs in series.

Typical wiring is (pins are numbered from the top view, starting at the bottom left corner and going counter-clockwise):

A 7

B 6

C 4

D 3

E 2

F 9

G 10

DP 8

COM 1,5

Since you have no idea if it's even CA or CC, you'll have to probe it. Take a power supply with 1kΩ resistor in series and start at 5V and work up, reversing the connections before increasing the voltage until you see adequate brightness from the segment or DP (don't exceed about 20mA though). Maybe the 'A' means it's CA, but maybe not.

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It should be fairly easy to figure this out without the datasheet, by using a multimeter on the "diode test" setting.

Pick any pin, and connect it to one of the multimeter's probes. Run the other probe along the remaining pins until a segment lights up. Note down which two pins light this segment.

Then move the first probe to the next pin, and repeat. Pretty soon you will find the common anode/cathode pin, because multiple segments will light in sequence when you run the other probe along the other pins.

From there you should be able to map out the segment pins too.

Edit: As it's a big display, the multimeter's diode test might not give enough current to light it (brightly enough, if at all). In that case, use a power supply with a resistor 1k or less.

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