Therefore care must be taken while measuring voltage using multimeter. It must be ensured that multimeter is selected in voltage mode before measuring voltage between two points. If by mistake, multimeter is selected in current mode and we measure the voltage between two points, this simply means we are connecting ammeter in parallel which means high current through the meter as well as circuit.
Modern Multimeter has inbuilt fuse, which will burn in this case. But for personal safety, it must be ensured that proper selection in Multimeter is done before the.
Ammeter measures value of current flowing in circuit, so current should flow inside ammeter to give proper result.
And it has very low resistance to ensure the correct measurement of current in the circuit. If it is connected in parallel across any load then all current in circuit will choose lower resistive path (i. e ammeter) to cause it s circuit to be damaged. Hence it is used in series.
And Voltmeter has very high resistance to ensure that it s connection do not alter flow of current in the circuit. Now if it is connected in series then no current will be there in the circuit due to it s high resistance. Hence it is connected in parallel to the load across which potential difference is to be measured.