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A multimeter is a type of electronic instrument that electronic technicians and engineers frequently use. It’s also known as a VOM (volt-ohm-milliampere) and is a multi-measurement electronic measuring device.
They’re used by electricians to troubleshoot electrical problems in motors, power supplies, appliances, circuits, and wiring systems. DIYers can also learn how to use multimeters to take basic measurements around the house.
It is used to measure voltage, current, and resistance, which are the three basic electrical characteristics. It can also be used to determine whether two points in a circuit are electrically connected.
They can be used for everything from simple testing like battery voltage measurement to fault detection and complex diagnostics, and they come in both analog and digital configurations.
Types of Multimeter
- Digital Multimeter: A measuring instrument, such as a digital multimeter, is the most widely used test equipment in various industries. It improves accuracy by obtaining multiple signal samples in less time. It also includes an automatic ranging feature, which eliminates the need for the operator to select the measurement manually.
- Fluke Multimeter: This multimeter is equipped with several features. This meter is used to calculate resistance and voltage and usually comes with a large display. It’s used to change the voltage, current, and electrical unit, among other things.
- Analog Multimeter: An analog multimeter, also known as a moving coil device, uses a microammeter and a needle to calculate voltage, current, and other parameters. You can easily calculate different quantities by changing the setting of the switch on the meter with the help of several removable probes.
- Clamp Multimeter: This multimeter has a clamp feature that calculates amps after the volts from the two probes have been calculated. By multiplying the voltage reading by the amps, you can adjust the power consumption. It also has a bonus feature that allows you to choose from a variety of settings.
- Autoranging Multimeter: There is a knob in the middle of this type of multimeter, and there are fewer positions. As a result, it is used in simple electronic projects and does not control by design to measure. For electricians and beginners, these tools are highly recommended. Normally, this meter only measures one component at a time.
Benefits of Multimeter
- The electrical output can be used to send and receive data with other devices.
- There is no effect from loading due to the high input impedance.
- A clear reading can be obtained at greater viewing distances.
- The display of the output can be done automatically.
- It can auto-polarize.
- These are less expensive because of the integrated technology.
Limitations of Multimeter
- The LCD is primarily powered by an external source, such as a battery because the LCD becomes dim and difficult to read when the battery is depleted.
- The meter must be used following the manufacturer’s specifications and the category rating; otherwise, the meter will be damaged, resulting in the loss of equipment.
- The multimeter’s limit is 1V, so if it’s exceeded, it’ll be damaged.
- Power supply and isolation requirements
- Testing for continuity and resistance
- Determining the frequency
- Testing the switch
- A faulty power cable can be identified.
- Testing the batteries
- An outlet can be tested.
- It’s used for environmental and temperature control.
- Diode testing
- AC/DC measurement
- Voltage measurement (AC/DC)
- Old incandescent light bulbs can be tested.
- Measurement of time and frequency
How to Use a Multimeter to Test Voltage of Live Wires?
Step1: Set the Parameters
Millimeters are designed to measure three different parameters, so set the selection knob to Voltage mode to measure voltage. A standard multimeter measures voltage between 200 mV and 600 V AC or DC.
To measure Alternating Current, use the part labeled V and a wavy line. To measure DC, use the V part and a straight line. To measure AC, use the V part and a straight line.
Step2: Plugin Probes
If you’re using a three-port multimeter, it has the following features:
- COM: The common port for measuring the circuit’s negative or ground potential.
- mAV Ω: For measuring resistance, voltage, and current up to 200
- mA 10A: For measuring resistance, voltage, and currents up to 200 mA to detect extremely high currents
All you have to do is plug the probes into the appropriate ports for the measurements you want to make.
Step3: Actual Testing
Test the multimeter on a real live wire to make sure it’s working properly. The first method involves using a red probe on the live cable and a black probe on the neutral cable.
Take a look at the result. The second method involves placing a black probe on the earth wire and a red probe on the live wire. The reading will come to you.
Step4: Take the Readings
When checking a wire with a multimeter, there are two scenarios in terms of readings.
The fixture is live if the voltage displayed on the display screen is between 110 and 120 volts. If the display screen reads zero, the wire has no voltage. To put it another way, the wire isn’t conducting any current.
- With your bare hands, never touch a live wire. Even if you’re just going to fix or move the cable, wear an insulating glove.
- Every time you want to measure an electrical value in an AC circuit, switch the multimeter from DC to AC mode.
- Before connecting or disconnecting a multimeter, make sure the circuit is completely de-energized and discharged.
- When measuring resistance with a multimeter, you should never apply power to the circuit.
- Begin your testing with the current range that has the highest current.
How to Use a Multimeter to Test Voltage of Live Wires?
A multimeter is a device that measures different aspects of your electrical system.
Testing the voltage of wires with an electronic multimeter is something that any homeowner can do. Simply follow the steps outlined above to test the voltage of wires.
You can read our blog on How to Test a Plug Socket with a Multimeter UK?
It’s best to use a non-contact volt tester or phase tester screwdriver for this. These will indicate if the voltage is greater than 100 volts, for example. A multimeter can only measure the voltage between live and live or neutral and earth if these terminals are available, which isn’t always the case.
When the voltage drops across a resistance or along a power cable, it is known as voltage drop. To compute voltage drop, rehash the cycle for estimating the voltage at the two focal points and take away one from the other.