Detailed Study of Range Extension of Dc Ammet...

Detailed Study of Range Extension of Dc Ammeter and Dc Voltmeter

Author Name : Pravin Patil, Shivraj Zende, Arvind Yadav, Atharv Patil, Prajwal Desai, Karan sandage

ABSTRACT In electrical measurement system, The measurement of direct current and voltage plays crucial role. The permanent magnet moving coil(PMMC) and Moving iron(MI) instruments has very low internal resistance. If they directly connected to measure voltage and current in circuit it will get damaged due to excessive current flowing through it. In this paper we are discussed the range extension of DC ammeter and DC voltmeter using a shunt resistor and series multiplier, respectively to measure direct current and voltage. The selection of appropriate values of shunt and multiplier is required for better accuracy and less errors. by connecting small valued resistor across the galvanometer it can be used to measure current and similarly by connecting high valued resistor across it. it can be used to measure voltage. by selecting different values of resistance the different ranges cab be obtained by single instruments. In this paper we have also discussed the multirange DC ammeter and multirange DC voltmeter .Calculation related to find appropriate value of resistor to be connected in circuit for range extension. Calibration of meters are also discussed