Measurement of A.C. voltage and current by multimeter

Aim: The aim of the experiment is to measure AC voltage and current using a multimeter.

Apparatus:

1. Multimeter: A digital or analog multimeter capable of measuring AC voltage and current.

2. Test leads: Detachable probes that come with the multimeter, typically red and black in color.

3. Power source: An AC power source or a circuit with an AC power supply.

Theory:

- AC Voltage Measurement: The multimeter measures the amplitude of alternating voltage between two points in a circuit. In AC voltage measurement, the multimeter applies a small known voltage across its probes and measures the voltage drop across the component or circuit being tested. The result is displayed in volts (V) and typically represents the RMS (Root Mean Square) value of the AC voltage.

- AC Current Measurement: The multimeter measures the flow of alternating electric current in a circuit. In AC current measurement, the multimeter is connected in series with the circuit being tested. It measures the current passing through it and displays the result in amperes (A). Similar to voltage, the displayed value typically represents the RMS value of the AC current.

Procedure:

1. Ensure that the multimeter is set to the appropriate mode for AC voltage and current measurements.

2. Connect the black probe to the COM (common) port of the multimeter.

3. Connect the red probe to the appropriate port based on the measurement being performed (VΩmA for voltage, 10A for current).

4. For voltage measurement:

   a. Ensure that the circuit or component is disconnected from the power source.

   b. Touch the black probe to the ground or neutral terminal of the circuit/component.

   c. Touch the red probe to the live or hot terminal of the circuit/component.

   d. Read the voltage value displayed on the multimeter's screen.

5. For current measurement:

   a. Ensure that the circuit is disconnected from the power source.

   b. Open the circuit and insert the multimeter in series with the component to measure the current.

   c. Connect the red probe to the positive side of the circuit and the black probe to the negative side.

   d. Make sure the current flows through the multimeter without exceeding its selected current range.

   e. Read the current value displayed on the multimeter's screen.

Results:

- The multimeter will display the measured AC voltage in volts (V) for voltage measurements.

- The multimeter will display the measured AC current in amperes (A) for current measurements.

Note: When measuring AC voltage or current, it is essential to take note of the frequency of the AC signal and ensure that the multimeter is suitable for measuring the specific frequency range. Additionally, ensure proper safety precautions are followed while working with AC power sources to avoid electrical hazards.