Voltage and Current Sensitivity of a Galvanometer


Current Sensitivity:

The deflection of a galvanometer per unit current is called current sensitivity of galvanometer.

$$ \text{i.e.,  } S_I =  \frac{ \theta }{I}……(i)$$

In a moving coil galvanometer,

$$k \theta =BINA$$

$$or, \frac{ \theta }{I}=  \frac{BNA}{k}  $$

From equation (i) and (ii),

$$S_I =   \frac{BNA}{k}$$

So, current sensitivity of a galvanometer can be increased by increasing the value of B, N and A. It can be decreased by decreasing the value of k.

Voltage Sensitivity:

The deflection of galvanometer per unit voltage is called voltage sensitivity of a galvanometer.

$$ \text{i.e.,  } S_v =  \frac{ \theta }{V}……(i)$$

In a moving coil galvanometer,

$$k \theta =BINA$$

$$or,  K \theta = B \frac{V}{R}NA$$

$$or,   \frac{ \theta }{V} =  \frac{BNA}{Rk} $$

So, voltage sensitivity of a galvanometer can be increased by increasing the value of B, N and A. It can be decreased by decreasing the value of R and k.

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6 Responses to “Voltage and Current Sensitivity of a Galvanometer”

  1. David

    Please endeavor to define the terms in the equations

  2. Harsha raibagi

    What is the range of figure of merit of ballistic galvanometer?

  3. Sai Charan Reddy

    Try to derive the terms in it

  4. chalani rasangi

    very bad.try to elaborate

  5. Soumyadeep

    If the current sensitivity is increased 50% of a moving coil galvanometer then the resistance becomes double, calculate the potential sensitivity of this galvanometer

    • Soumyadeep

      Answered my question