Question

What is the formula for the conversion of galvanometer into voltmeter?

Answer 1

To convert a galvanometer into a voltmeter, you can use the following formula:

\[
V = G \left( 1 + \frac{R_g}{R} \right)
\]

Where:
- \( V \) is the maximum voltage that the voltmeter can measure.
- \( G \) is the full-scale deflection current of the galvanometer.
- \( R_g \) is the internal resistance of the galvanometer.
- \( R \) is the resistance of the shunt resistor added in parallel with the galvanometer.

The shunt resistor \( R \) is added to allow the galvanometer to measure higher voltages without exceeding its full-scale current. The appropriate value of \( R \) can be calculated using:

\[
R = \frac{R_g \cdot (V_g)}{I_g}
\]

Where:
- \( V_g \) is the maximum voltage across the galvanometer (usually the full-scale voltage).
- \( I_g \) is the full-scale deflection current of the galvanometer.

This setup allows the galvanometer to measure higher voltages accurately.

Answer 2

To convert a galvanometer into a voltmeter, you need to use a shunt resistor. The formula for this conversion can be expressed as:

\[ V = \frac{G \cdot R_g}{R_s} \]

where:
- \( V \) is the voltage you want to measure,
- \( G \) is the full-scale deflection current of the galvanometer,
- \( R_g \) is the internal resistance of the galvanometer,
- \( R_s \) is the resistance of the shunt resistor.

You can calculate the required shunt resistor \( R_s \) using:

\[ R_s = \frac{R_g \cdot I_g}{V - I_g \cdot R_g} \]

where \( I_g \) is the current through the galvanometer at full scale. This setup allows the galvanometer to measure higher voltages than its original capacity. Would you like to delve deeper into any specific aspect of this conversion?