Why Current Sensing Uses Shunts, Hall Sensors, and CTs
Current sensing is easy to underestimate. An ADC reads voltage, not current. To measure current, the system must first convert current into something measurable.
The first model is: current must be transformed into voltage, magnetic field, or induced current before electronics can measure it.
Shunt resistor: current -> voltage drop
Hall sensor: current -> magnetic field -> Hall voltage
Current transformer: AC current -> magnetic flux -> induced current
These are not three interchangeable implementations of the same idea. They have different physics and tradeoffs.
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