# Multimeter measures resistance when there’s no battery attached?

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In summary, a multimeter measures resistance by passing a small current through a circuit and measuring the resulting voltage drop. This is made possible by a built-in battery that provides a small amount of voltage. However, the resistance measurement is still accurate without a battery. The multimeter can only measure resistance in a closed circuit and the measurement will not change if the battery is removed. In the AC mode, the multimeter can also measure resistance without a battery using the impedance method.
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How does the multimeter measures resistance when there’s no battery attached?

A multimeter has its own battery inside.

A multimeter measures resistance by using a small known current and measuring the resulting voltage drop across the component being tested. This is known as Ohm's Law, where resistance (R) is equal to voltage (V) divided by current (I).
In the case of testing resistance without a battery attached, the multimeter is still able to generate a small current through its own internal circuitry. This current is then used to measure the voltage drop across the component, allowing the multimeter to calculate the resistance.
It is important to note that the internal current generated by the multimeter is typically very small and should not affect the accuracy of the resistance measurement. However, it is always recommended to use a battery when testing resistance to ensure the most accurate results.

## 1. Why does a multimeter measure resistance when there's no battery attached?

Multimeters have a built-in battery that provides a small amount of voltage for resistance measurements. This allows the multimeter to pass a small current through the circuit and measure the resulting voltage drop, which is used to calculate the resistance.

## 2. Is the resistance measurement accurate without a battery?

Yes, the resistance measurement is still accurate without a battery. The multimeter's battery provides a small amount of voltage, but it is not necessary for the resistance measurement. As long as the multimeter is functioning properly, the measurement will be accurate.

## 3. Can a multimeter measure resistance without a battery in any circuit?

No, a multimeter can only measure resistance in a closed circuit. If there is an open circuit or a break in the circuit, the multimeter will not be able to measure resistance even with a battery attached.

## 4. Does the resistance measurement change if the battery is removed?

The resistance measurement will not change if the battery is removed as long as the circuit remains the same. However, if the circuit is altered in any way, the resistance measurement may also change.

## 5. Can a multimeter measure resistance without a battery in the AC mode?

Yes, a multimeter can measure resistance without a battery in the AC mode. The AC mode uses a different method of measuring resistance, called the impedance method, which does not require a battery. However, the multimeter may still have a built-in battery for other functions in the AC mode.

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