What is the advantage of choosing a current sensing device over a voltage sensing device for an analog input?

• A. The current sensing device is less susceptible to noise
• B. It is cheaper
• C. It has higher input impedance
• D. It consumes less power

Answer: (A)

Noise immunity and signal integrity over wiring are the main ideas here. A current sensing setup carries the measurement as a current rather than a voltage, which makes it far less susceptible to the effects of long cables, ground differences, and electrical noise. In a current loop, the transmitter enforces a specific current through the loop, and the sensing stage at the receiver converts that current to a voltage locally (often via a shunt resistor) for the ADC. Because the current remains defined along the entire path, voltage drops, cable impedance, and interference have much less impact on the signal value you measure. A voltage-based approach, by contrast, is more vulnerable to these issues: the same wiring resistance and noise can distort the voltage arriving at the input, degrading accuracy. So the core benefit is improved robustness to noise and disturbances in real-world wiring conditions, especially for longer runs. Other factors like cost, input impedance, or power can vary, but they don’t beat the noise immunity advantage of current sensing.