How is current measured across a current shunt?

To measure current across a current shunt, voltage is utilized. A current shunt is essentially a low-resistance resistor that is placed in series with a load in order to measure the current flowing through that load. When current flows through the shunt, a voltage drop is developed across it due to its resistance. This voltage is proportional to the amount of current flowing according to Ohm’s Law (V = I × R), where V is the voltage drop, I is the current, and R is the resistance of the shunt.

By measuring this voltage drop, it is possible to calculate the current since the resistance of the shunt is known. This method is preferred because it allows for precise current measurements with minimal impact on the overall circuit operation, as the shunt creates a small voltage drop compared to the load.

The other choices do not appropriately represent how current is measured in this context. Current is the quantity being measured, whereas ohms refers to resistance. The pH scale is unrelated to electrical measurements and applies to acidity or alkalinity rather than current measurement. Thus, voltage emerges as the correct and relevant measure in this scenario.