I am still thinking about the power supply for a project. I am wondering why Arduino is not build for 5V power input. Is that just because there is still the possibility to input 5V on the PIN (is that possible, BTW?), or is there a deeper reason one should design for 7-12V?

Why don't Arduinos run on 5V

CrossRoads August 26, 2012, 3:54pm 9

Someone posted last night about a 'noisy' 5V wallwart - the noise was showing up in the PWM output signal and affecting audio results.

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