Question

What is resistance of voltmeter?

Answer 1

1. The opposition that a substance provides to the flow of electric current is known as resistance. The uppercase letter $R$ is used to signify it.
2. A voltmeter, often known as a voltage meter, is a device that measures the voltage differential between two points in an electrical or electronic circuit. Some voltmeters are designed for direct current (DC) circuits, while others are for alternating current (AC) circuits.
3. Voltmeters measure voltage differences between two points, such as opposite ends of a resistor, but they shouldn't affect the current flowing through the element between these two sites. Therefore, it must have an extremely high resistance so that current cannot flow through it.
4. The resistance of the voltmeter is infinite since it should not allow any current to through the voltmeter.
5. To measure the potential difference between two points, a voltmeter is connected in parallel to the current carry wire. A finite quantity of current will run through it because it is connected through the wire.
6. This will result in a change in the actual current flow and, as a result, a change in the actual potential difference. To avoid this, a voltmeter's resistance is set high enough that the current going through it is kept to a minimum.
7. However, the reading would still have some flaws as a result of this. There should be no current flowing through the voltmeter in an ideal circumstance, where it can measure the true potential difference between two places, and hence its resistance should be infinite.
8. The diagram of the voltmeter is given below:

1. Diagram of the resistance of the voltmeter

Thus, the resistance of a voltmeter should be very high, ideally infinity.