Multimeter: Definition, Functions, Principles, Maintenance and Trends

Jul 03,2023
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What is a multimeter?

Multimeter, also called a volt-ohmmeter (VOM), is an electronic instrument used to measure various electrical quantities in a circuit. It is a multifunctional tool that combines several measurement functions into one device. The most common measurements for multimeters include voltage, current and resistance.

What are the functions of multimeter?

A multimeter is an instrument with multiple functions. Common features include:

① Voltage measurement: It can measure direct current (DC) voltage and alternating current (AC) voltage. Enables the user to measure the voltage of the component, circuit or power supply.

② Current measurement: The multimeter can measure DC and AC current. Allows the user to measure the current flowing through a circuit or component.

③ Resistance measurement: The multimeter can measure resistance. This feature is useful for testing resistors, checking continuity, and identifying opens or shorts.

④ Diode test: usually has a diode test mode function, which allows users to test the forward and reverse bias characteristics of the diode. Helps identify faulty or damaged diodes.

⑤ Capacitance measurement: Some multimeters have a flashlight measurement function, which can measure the capacitance of capacitors. Useful for testing and selecting capacitors in electronic circuits.

⑥ Temperature measurement: Some multimeters also have the function of temperature measurement. Allows the user to measure temperature using a temperature probe or thermocouple. This feature is helpful in a variety of applications including HVAC systems and temperature-sensitive electronic components.

⑦ Frequency Test: Advanced multimeters may have a frequency measurement mode that enables the user to measure the frequency of an AC signal. It is especially useful in electronic circuit analysis and troubleshooting.

⑧ Continuity Test: The multimeter has a continuous mode, which can check whether there is a continuous electrical connection between two points, when there is continuity, it will beep or display a value close to zero ohms, indicating that the circuit or connection is complete.

Different multimeters may have different additional and specialized functions. This depends on its design and intended application. Always consult the owner's manual or guide before use.

How does the multimeter work?

The working principle of the multimeter is to use different measurement techniques to measure electricity.

While there are many types of multimeters, the common type is the digital multimeter (DMM), which uses analog-to-digital conversion to display measurements on a digital screen. Here is an overview of how a multimeter generally works:

① Voltage measurement: When measuring voltage, connect the multimeter in parallel to the circuit or component under test. In this mode, the multimeter acts as a high-resistance voltmeter. It uses a voltage divider circuit and an analog-to-digital converter to measure the voltage and display it on the screen.

② Current measurement: Connect the multimeter in series to the circuit when measuring current. In this mode, the multimeter acts as a high-resistance voltmeter. It uses a voltage divider circuit and an analog-to-digital converter to measure the voltage and display it on the screen.

③ Resistance measurement: When measuring resistance, the multimeter makes a known small current flow through the component, measures the voltage drop across it, and then uses Ohm's law to calculate the resistance.

④ Diode test: When testing a diode, the multimeter applies a small forward bias voltage and measures the resulting current. It detects the direction of current flow and displays the forward voltage drop across the diode, indicating its functionality.

⑤ Other measurements: Advanced multimeters can use other techniques to measure capacitance, frequency, temperature, and other quantities. These measurements involve different measurement circuits and sensors specific to the respective quantities.

Different multimeters have different accuracies, measurement ranges, and capabilities, so it is critical to refer to the manufacturer's instructions and specifications to ensure proper use and accurate measurements for your particular multimeter model.

Maintenance tips of multimeter

During normal use, multimeter maintenance helps ensure its accuracy, reliability and longevity. Here are some tips for maintaining your multimeter:

① Regular calibration: Calibration is very important to ensure the accuracy of multimeter measurement. Regular multimeter calibrations by professional calibration services and technicians are recommended.

② Keep the test leads clean: The test leads of the multimeter are the main interface between the instrument and the circuit under test. Over time, test leads can accumulate dirt, oil, or oxidation, which can affect the quality of the electrical connection and cause measurement errors. Clean the test leads periodically with a soft cloth and, if necessary, with a mild cleaning solution.

③ Protect from moisture and extreme environments: Keep the multimeter away from moisture and extreme temperatures. Exposure to these conditions may damage internal components and affect the multimeter's performance. When we are not using our multimeters, store them in a dry and temperature-controlled environment.

④ Use the correct measurement range: Using the incorrect range may result in inaccurate readings and potential damage to the multimeter. Start with the highest range and gradually decrease the range until the desired measurement is obtained.

⑤ Avoid overload: Make sure the measured value is within the current and voltage limits of the multimeter. Exceeding the specified limits may damage the multimeter and reduce its accuracy.
⑥ Replace the battery in time: If the multimeter is powered by a battery, please monitor the battery power regularly. When the battery power is low, it should be replaced in time to avoid sudden power failure during the measurement process.

⑦ Avoid excessive force: Avoid excessive force when connecting or using rotary switches and buttons. Excessive force may damage internal components and affect the accuracy and functionality of the multimeter.

These little maintenance tips above can help keep your multimeter in good working order and ensure accurate and reliable measurements throughout its useful life.

With the advancement of science and technology, multimeter technology is becoming more and more mature. Not only can they be integrated with smart devices, but they can also be connected wirelessly to transmit data to other devices.Users can easily share measurement data, collaborate with colleagues or store data for future analysis.

For example:

P03 EV Integrated Detection Tool is a high-tech product that integrates multiple functions such as oscilloscope, multimeter, current clamp and insulation test. The versatility of this equipment meets the different needs of customers and effectively saves costs. iSmartEV P03 is truly an outstanding product with its cost-effective features.

OM201 Two-channel Oscilloscope & Multimeter is a device that integrates the functions of oscilloscope and multimeter. It is designed for current, voltage and resistance measurement in electric vehicles.  iSmartEV OM210 is easy to operate and has multiple functions. When used together with iSmartEV P01, it supports both wireless and wired communication methods, providing users with a convenient measurement experience.

In the future, multimeter technology may also integrate artificial intelligence (AI), using AI algorithms to provide enhanced measurement accuracy, automatic range selection or predictive maintenance functions. AI-driven multimeters can learn from past measurements and adjust their measurement techniques to improve accuracy and efficiency. As technology continues to advance, multimeters will become more sophisticated, connected and user-friendly, providing professionals in various industries with improved measurement capabilities and convenience.


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