What happens if a voltmeter is not ideal?

But when considering a non ideal voltmeter the resistance is not infinite and therefore there will be a current in the closed loop circuit involving the cell and the voltmeter.

How does the voltmeters resistance affect measurements?

Now, the voltmeter can only indicate the voltage its connected across. The very act of connecting the voltmeter to the circuit makes it part of the circuit, and the voltmeter’s own resistance alters the resistance ratio of the voltage divider circuit, consequently affecting the voltage being measured.

Would you expect a good voltmeter to have a low or high internal resistance?

The best voltmeter will have such a high resistance that it will not significantly change the current in the circuit. Ideally, an ammeter should have zero resistance and a voltmeter infinite resistance to give correct readings.

Why does the ideal voltmeter have high resistance?

On the other hand, a voltmeter measures the voltage difference between two different points (say, on different sides of a resistor), but it should not change the amount of current going through the element between those two points. So, it should have very high resistance so that it doesn’t “draw” current through it.

How does changing the resistance affect the reading on the voltmeter?

Usually the resistance of the coil used in a voltmeter is very high, and if it is connected in series with any component, it basically causes a large voltage to drop across itself thereby altering the value of current in that branch.

Why does ideal voltmeter have infinite resistance?

A voltmeter is used to measure the potential difference across the two points of a circuit. For it, the voltmeter is connected in parallel across those two point. The potential difference measured by voltmeter will be accurate if no current is drawn by voltmeter. Thus, ideal voltmeter has infinite resistance.

Why it is necessary for voltmeter to have a high resistance?

A voltmeter measures the voltage difference between two different points, but it should not change the amount of current going through the element between those two points. So, it should have very high resistance so that it doesn’t allow current to pass through it.

How does the voltmeter reading change as the ammeter reading increases?

The ammeter reading is related simply to the voltmeter reading. The current through the ammeter is given by , where is the voltage between points 1 and 3, which is exactly the voltage that the voltmeter reads. The voltmeter reading would stay the same; the ammeter reading would increase.