# How to calculate the percentage error for moving iron voltmeter?

• kloong
In summary, a moving iron voltmeter is an instrument used to measure the voltage of an electrical circuit. Percentage error for this type of voltmeter can be calculated by taking the absolute value of the difference between the measured and true values, dividing by the true value, and multiplying by 100. The true value is the actual voltage of the circuit, and an acceptable percentage error is generally less than 5%. To reduce percentage error, a more accurate voltmeter, proper calibration, and minimizing external influences can be helpful. It's also important to take multiple measurements and calculate an average.

#### kloong

the moving iron voltmeter has resistance of 5k ohm at 15c when it reads correcectly when connected to a supply of 200V.
and the copper coil's temperature coefficient at 15c is 0.004ohm/c.

so what's the percentage error in the reading when it's 50c?

Does the temperature coefficient remain the same from 15C° - 50C°?

Before we can help, you have to provide an attempt at the solution. Or do you have a question about the problem statement itself?

oh, it's ok now. I've got it already. thanks anyway. =)

## 1. What is a moving iron voltmeter?

A moving iron voltmeter is an instrument used to measure the voltage of an electrical circuit. It works by using a piece of iron that moves in response to the magnetic field created by the current in the circuit. The greater the voltage, the stronger the magnetic field and the more the iron moves.

## 2. How is percentage error calculated for a moving iron voltmeter?

The percentage error for a moving iron voltmeter is calculated by taking the absolute value of the difference between the measured value and the true value, dividing it by the true value, and then multiplying by 100. The formula is: (|measured value - true value| / true value) x 100.

## 3. What is the true value in the percentage error calculation for a moving iron voltmeter?

The true value in the percentage error calculation for a moving iron voltmeter is the actual voltage of the circuit being measured. This can be determined through calibration or by using a known voltage source.

## 4. What is an acceptable percentage error for a moving iron voltmeter?

The acceptable percentage error for a moving iron voltmeter depends on the application and the level of accuracy required. Generally, a percentage error of less than 5% is considered acceptable, but for more precise measurements, a lower percentage error may be necessary.

## 5. How can the percentage error be reduced for a moving iron voltmeter?

The percentage error for a moving iron voltmeter can be reduced by using a more accurate voltmeter, ensuring proper calibration, and minimizing external influences such as temperature and electromagnetic interference. It is also important to take multiple measurements and calculate an average to reduce random errors.