Question

What is the working principle of voltmeter?

Answer 1

Hint: Let us get some idea about the voltmeters. A voltage metre is a device that measures voltage. The voltage between the two nodes is measured with this device. Volts are the unit of potential difference. As a result, it is a measuring device that determines the potential difference between the two points.

Complete step by step answer:
The basic premise of a voltmeter is that it must be linked in series with the voltage we wish to measure. Because a voltmeter is built in such a way that it has a very high resistance value, a parallel connection is used. When that large resistance is linked in series, the current flow is nearly zero, indicating that the circuit is now open.
If it's connected in parallel, the load's impedance will be parallel to the voltmeter's high resistance, resulting in a combination that has nearly the same impedance as the load. Also, because the voltage in a parallel circuit is the same, the voltage between the voltmeter and the load is nearly the same, and the voltmeter measures the voltage.
In an ideal voltmeter, the resistance is infinite, and so the current drawn is zero, resulting in no power loss in the instrument. However, this is impossible to do in practise since no material can have infinite. resistance.

Note: General-purpose analogue voltmeters are used with voltages ranging from a fraction of a volt to several thousand volts and have an accuracy of a few percent of full scale. Digital metres have a high degree of accuracy, often better than \[1\% .\]Higher accuracies can be achieved with specially calibrated test instruments, with laboratory tools capable of measuring to a few parts per million.