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seven segment help

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Well-Known Member
Most Helpful Member
I would try adding a resistor (say 500Ω) in series with one of the segments and slowly increase the voltage until you get the desired brightness. Then measure the voltage across the resistor and calculate the current (or connect an ammeter in series with the resistor to find the current). I expect it will be somewhere around 10-20mA. From that you can calculate the required resistor value for the voltage supply you have.

If you go too high in current the brightness will seem to stop increasing with current. At that point you would be overdriving the LED.


New Member
Maybe this info is of no use since it's a long time question was raised but I've bought same 7 seg displays on ebay and here are some info
Common Cathode
Size: 2.3'' (69.70mm*47.80mm*12mm)
Forward Voltage: 7.5V
Forward Current: 5-10mA
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