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Better way to connect LEDs to the MCU pin

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tiwari.sachin

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Whats the better way to connect LEDs to MCU (microcontroller) pins

1. MCU Pin to Anode of LED (Source Current)

2. MCU Pin to cathode of LED (Sink Current)


I have had some issues when sourcing current (option 1). after continuous usage, the pin of MCU was damaged.
 

The best way is to use a general purpose NPN transistor to drive anything larger than a few milliamps out of a MCU port.
 

the best way is to read the max current ratings and use the recommended rating instead.
Some are asymmetrical with more sink current, meanwhile some LEDs are ultrabright at 2~3mA
 

I don't think 20 mA output current is supported by all microcontrollers.
Use the NPN transistor I advised.
 

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