# 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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## One Response to “Voltage and Current Sensitivity of a Galvanometer”

Please endeavor to define the terms in the equations