Question

Which type of instruments do NOT have a NON-linear scale?
1. Moving Iron
2. PMMC
3. Electrostatic
4. EMMC

Answer 1

Correct Answer - Option 2 : PMMC

Concept:

In EMMC instruments, the deflection is directly proportional to the square of the current. i.e. θ ∝ I2

In moving iron instruments, the deflection is directly proportional to the square of the current. i.e. θ ∝ I2

In electrostatic, the deflection is directly proportional to the square of the voltage. i.e. θ ∝ V2

In moving-coil instruments, the deflection is directly proportional to the current. i.e. θ ∝ I

Application:

Electrostatic instruments, moving iron instruments and EMMC instruments have non-linear or non-uniform scale.

Moving coil instruments (PMMC) have a uniform or linear scale.