Which is better, a clamp meter or a multimeter? The difference between a clamp meter and a multimeter

Clamp meters and multimeters have their own advantages and disadvantages depending on the places where electricians use them. It is impossible to simply say which one is better or worse than the other.

★Clamp meters are divided into mechanical pointer clamp meters and digital clamp meters. Its biggest advantage is that it can measure the current in the circuit without disconnecting the measured circuit.

Regardless of the type of clamp meter, it generally only measures AC current, and there are also some clamp meters specifically for measuring DC current. The more popular digital clamp meters are shown below.

In order to ensure accurate and safe measurement, the clamp ammeter should be inspected as follows before use.

① Appearance inspection: There should be no defects such as damage. In particular, the jaws should be tightly closed and the iron core should be free of rust and dirt.

② If it is a mechanical pointer clamp meter, the pointer should point to "0" at this time, otherwise it should be adjusted to "0".

③ Estimate the magnitude of the current to be measured and select the appropriate gear. The principle of gear selection is: adjust to the gear that is larger than the measured value and close to it.

When measuring, open the jaws, clamp the measured wire into the jaws, close the jaws, and the needle will deflect to read the measured current value. Before reading, the clamp meter should be placed as flat as possible (mechanical pointer clamp meter), but it does not matter for digital clamp meters.

★Things to note when measuring with a clamp ammeter

① During the test, gloves should be worn (insulated gloves or clean and dry wire gloves), and a guardian should be appointed if necessary.

② When it is necessary to change gears for measurement, the wire should be withdrawn from the jaws first, and then the wire should be clamped in for measurement after changing gears.

③The voltage of the measured conductor cannot exceed the voltage level of the clamp meter.

④ It is prohibited to use clamp meters to measure poorly insulated and bare wires.

⑤ When measuring, be sure to keep a safe distance from nearby charged objects, and be careful not to cause phase-to-phase short circuits and phase-to-ground short circuits.

⑥ It is not suitable to measure line current in high temperature environment. It is not suitable to measure near strong magnetic field. The external magnetic field has a great influence on the measured value. The clamp ammeter should not be measured near the busbar and high-capacity motors, transformers and other high-load current equipment. It should be measured in another place to reduce the error short circuit caused by the magnetic field.

⑦ Measurements should not be made in humid places or during thunderstorms, because the clamp meter must be held directly for measurement of operating electrical equipment. The jaws, handle and hands of the clamp meter must be kept clean and dry during measurement.

⑧ The clamp ammeter has large errors in measuring non-rated currents. The working principle of the clamp ammeter determines that the clamp meter must be used under the specified rated rate. In addition to measuring sine wave currents, other waveform currents will produce errors. Generally, the waveform errors of odd harmonics are larger than those of even harmonics, especially the third harmonic has the largest error. When using a clamp ammeter to measure half-wave rectified current, the error is also large.

⑨ After use, the gear should be set to the highest current gear, and the meter should be placed in the meter cover if there is one, and stored in a dry, dust-free, non-corrosive gas and vibration-free place.

⑩ High-voltage current cannot be measured. The voltage of the circuit under test cannot exceed the rated voltage of the clamp ammeter. The clamp ammeter cannot measure high-voltage electrical equipment.

♥Multimeter has many uses, wide range, and is easy to use. It is the most commonly used tool in electrical measurement. In electrical maintenance work, it can be used to measure resistance, AC and DC voltage and DC current. Some multimeters can also measure the main parameters of transistors and the capacitance of capacitors. Mastering the use of a multimeter is a basic skill in electrical technology.

Common multimeters include pointer multimeters and digital multimeters. Pointer multimeters are multifunctional measuring instruments with the meter head as the core component. The measured value is read by the meter head pointer. The measured value of the digital multimeter is directly displayed in digital form on the LCD screen. It is easy to read and some of them also have voice prompts. A multimeter is an instrument that uses a common meter head and integrates a voltmeter, an ammeter and an ohmmeter.