# 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”

Please endeavor to define the terms in the equations

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

Try to derive the terms in it

very bad.try to elaborate

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

Answered my question