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prusa3d / MK3_Power_Panic

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Replace 11k resistor with cap #7

Closed luxarts closed 6 years ago

luxarts commented 6 years ago

Hello!

I was suprised when I saw the 8 resistors at the AC input. Why not a capacitor? I don't think the phase shift between voltage and current matters. The total resistance it's 88k. In my country the frequency of the AC it's 50Hz. Doing the math:

Xc = 1/(2 π freq c) -> c= 1/(2 π freq Xc)

To get 88k: 1/(2 π 50 * 88k) = 36.17nF aprox. The close comercial value it's 39nF, getting 81.6k aprox.

Less power disipation, less heat, less footprint.

Regards, Lucas

ok1hra commented 6 years ago

Yes, but high voltage capacitor more expensive than resistors.

boelle commented 6 years ago

i agree with @ok1hra, the power consumption is 150 mW and replacing the resistors with a capacitor to save a little just dont justify the more expensive capacitor