Chapter 24, Problem 62A

To determine

To identify: The type of device represented by given circuit.

Answer to Problem 62A

The given arrangement leads to an ammeter.

Explanation of Solution

Given:

A galvanometer with a resistor connected in parallel to it.

Consider the circuit shown in Figure 1. The circuit consists of a galvanometer which can be used to measure small currents. The resistor connected in parallel with the galvanometer is called as “shunt resistor”. This resistor has a value less than the resistance of the galvanometer. It is converted to an ammeter using circuit.

  

Figure 1

In this circuit, the effective resistance of the coil of the galvanometer is reduced from its original value of around 1000 Ω to a lower value decided by the shunt resistance across the meter. Due to the presence of shunt resistance, more current flows through the shunt resistor than the galvanometer. This produces a corresponding deflection in the meter scale and hence measures the current.

Thus, the given circuit works as an ammeter.