• Suppose 3 resistances are R1, R2 and R3. We will connect these resistances in parallel with an ammeter (A), a voltmeter (V), a plug key (K)and a battery of known voltage as shown in figure given below.
• We will close the key K and record the ammeter and voltmeter readings.

• Now we will open the key and switch the position of voltmeter and ammeter as show in the figure given below.

• We will close the switch and note the readings. Similarly, we will switch the position of voltmeter to resistances R2 and R3 and observe the readings.
• We will find that readings of ammeter keeps on changing but readings of voltmeter in all cases almost remain same in all cases.