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Common cathode or common anode leds

e14 Contributor

I'd like to use 7 segment leds and led arrays. Are there any pros and cons regarding using common cathode or common anode devices  - ?

Thank you.

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    John de B

     

    Common anode allows you to switch the individual leds to ground, hence simple NPN transistors.

    This allows you the option of controlling the voltage applied to the anode and hence the final brightness of all leds very simply.

     

    Depending on your controlling hardware, it can also simplify the code ie output HIGH is led ON.

     

    As john said it depends if you have access to an existing supply.

     

     

    Be aware that switching seven segment leds can create electrical hash. Just try a radio next to a bedside clock that uses 7 seg leds....

     

    Mark

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  • 0

    John de B

     

    Common anode allows you to switch the individual leds to ground, hence simple NPN transistors.

    This allows you the option of controlling the voltage applied to the anode and hence the final brightness of all leds very simply.

     

    Depending on your controlling hardware, it can also simplify the code ie output HIGH is led ON.

     

    As john said it depends if you have access to an existing supply.

     

     

    Be aware that switching seven segment leds can create electrical hash. Just try a radio next to a bedside clock that uses 7 seg leds....

     

    Mark

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