What is Multimeter? – Construction, Operation, Function | New Topic [2024]

In this note, we are going to talk about a topic called “What is Multimeter?“, and also learn about its operation and functions. Welcome to Poly Notes Hub, an one stop solution for engineering notes.

Author Name: Arun Paul.

What is Multimeter?

A Multimeter is an electronic device that can measure resistance, current, and voltage. It is a must-have tool for monitoring both alternating current and direct current voltages and currents. A multimeter is the most inexpensive piece of equipment and can perform a variety of electrical measurements with reasonable precision.

A multimeter, commonly known as a volt-ohm meter (VOM), is a flexible electronic device for measuring voltage, current, and resistance in electrical circuits.

Types of Multimeter

There are two types of multimeter, which are listed below –

1. Analog Multimeter
   • Analog multimeters display measurements using mechanical movement, usually a needle on a scale.
   • They have a simpler design than digital multimeters.
   • Analog multimeters are frequently selected for activities that require monitoring quickly changing values because the needle provides a visual indication of fluctuations.
   • They are typically less expensive than digital multimeters.
   • Analog multimeters may require manual zero-ohm adjustment and calibration.
   • They may be more prone to reading errors due to parallax.
2. Digital Multimeter
   • Digital multimeters use digital screens, often LCD or LED, to display numerical measurements.
   • They have superior accuracy and resolution than analog multimeters.
   • DMMs frequently incorporate extra capabilities like auto-ranging, which automatically determines the right measurement range, and data hold, which freezes the displayed number for easy viewing.
   • Digital multimeters are more versatile, measuring a broader variety of parameters.
   • They are typically easier to read and interpret, particularly for exact measurements.
   • DMMs may include advanced features such as connecting to computers or cellphones for data logging and analytics.
   • They require batteries to operate and may need to be replenished on a regular basis.

Construction of Multimeter

Below we discuss about the multimeter construction in list format, which is easy to understand –

• Display: The front-facing component of the multimeter has a digital display that shows the measured values. This could be a liquid crystal display (LCD) or a light emitting diode (LED).
• Function Selector Switch: This switch allows the user to choose the kind of measurement (voltage, current, or resistance). It often has multiple places that correlate to distinct measurement functions.
• Input Jacks: The front panel normally contains two or more input jacks. These are where you connect the test leads (probes) to take measurements. These jacks are commonly labeled as “COM” (common), “VΩmA” (voltage, resistance, and current), with extra jacks for specific functions such as capacitance or temperature measurement.
• Test Leads: Multimeters have detachable test leads, which typically consist of a red lead for positive connections and a black lead for negative/common connections. These are attached to the input jacks and used to make contact with the circuit being tested.
• Protection Circuitry: Modern multimeters frequently feature protection circuitry to avoid damage to the meter or the circuit under test in the event of improper connections or excessive input voltages.

Functions of Multimeter

A multimeter can measure voltage, current, and resistance. To accomplish this goal, suitable circuits are integrated with the galvanometer. The galvanometer in a multimeter is always of the left zero type, which means that its needle rests in the extreme left position as opposed to the center zero position of regular galvanometers.

Multimeter functions (in shorts) that we are have to know –

1. Measuring of voltage.
2. Measuring of current.
3. Measuring of resistance.
4. Capacitance measurement (in some models)
5. Frequency measurement (in some models)
6. Temperature measurement (in some models)
7. Duty cycle measurement (in some models)
8. Transistor testing (in some models)

Applications of Multimeter

Multimeter applications or Multimeter Uses that we are listed below are very important –

1. Troubleshooting electrical circuits
2. Testing batteries
3. Checking continuity in wires and connections
4. Measuring voltage drops across components
5. Verifying proper operation of switches and relays
6. Diagnosing problems in electronic devices
7. Assessing the health of electrical systems
8. Testing components such as resistors, capacitors, and diodes