The d'Arsonval movement is a moving coil meter commonly used in which circuit type?

The d'Arsonval movement is a moving coil meter commonly used in which circuit type?

• A. DC circuit
• B. AC circuit
• C. High-frequency circuit
• D. Low-impedance circuit

Answer: (A)

The d'Arsonval moving-coil meter works by a coil placed in a fixed magnetic field. The torque on the coil is proportional to the current flowing through it, so the needle deflects in a direction and distance corresponding to that current. This setup behaves predictably only when the current is steady, i.e., in a DC circuit, where the direction doesn’t change and the deflection can settle to a proportional reading. In an AC circuit, the current reverses each half cycle, so the torque on the coil reverses too. Without any rectification, the average torque is near zero and the needle won’t give a meaningful, steady reading. It would also struggle to respond accurately to high-frequency signals because the coil and springs have a finite mechanical response time, which blunts rapid changes. So, the d'Arsonval movement is best suited for DC circuits.

The d'Arsonval moving-coil meter works by a coil placed in a fixed magnetic field. The torque on the coil is proportional to the current flowing through it, so the needle deflects in a direction and distance corresponding to that current. This setup behaves predictably only when the current is steady, i.e., in a DC circuit, where the direction doesn’t change and the deflection can settle to a proportional reading.

In an AC circuit, the current reverses each half cycle, so the torque on the coil reverses too. Without any rectification, the average torque is near zero and the needle won’t give a meaningful, steady reading. It would also struggle to respond accurately to high-frequency signals because the coil and springs have a finite mechanical response time, which blunts rapid changes.

So, the d'Arsonval movement is best suited for DC circuits.