Current sensing
Choose a current-sense shunt (drop, power rating, error), the gain of a current-sense amplifier into an ADC (INA180 A1–A4), the INA219's calibration register and LSBs, and scale a Hall-effect sensor such as the ACS712.
Added
How to use it
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Shunt resistor — R = Vdrop/Imax, its dissipation at full current and the power rating to buy (2× margin), and the full-scale error from its tolerance and temperature coefficient; with notes on Kelvin connections and high- vs low-side sensing.
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Amplifier into an ADC — the output at full current and the current per ADC step for each INA180 gain (20, 50, 100, 200 V/V), and the largest gain that doesn’t clip.
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INA219 calibration — the current LSB, the calibration register value Cal = trunc(0.04096/(Current_LSB·R)), the power LSB and the PGA range, from the datasheet.
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Hall-effect — ACS712 output voltage for a current and the current for a measured voltage.
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