Question

A PMMC rated as 100 μA is used in a rectifier type of instrument which uses full wave rectification. What is the sensitivity on sinusoidal AC?

(a) 4.5 kΩ/V

(b) 18 kΩ/V

(c) 10 kΩ/V

(d) 9 kΩ/V

The question was asked in homework.

My question is taken from Advanced Problems on Indicating Instruments topic in portion Extension of Instrument Ranges of Electrical Measurements

Answer 1

Right choice is (d) 9 kΩ/V

For explanation I would say: Sensitivity = \(\frac{1}{100 × 10^{-6}}\) = 10 kΩ/V

For full-wave rectification SAC = 0.9 + SDC = 0.9 × 10 = 9kΩ/V.