Current Sense Resistors
High current sensing is where a low ohmic precision resistor is used in series with the load. To determine the current one measures the voltage drop across the resistor. This is the same principal used by a shunt ammeter. The dilemma facing the designer is the conflict between minimizing heat generation and power loss (P=I2R) by choosing a low resistance, versus a choosing a higher resistance that results in an easier to measure voltage drop.