Voltan testing item for digital multimeters
Satu daripada the most basic functions of a digital multimeter is to measure voltage. Testing voltage is usually the first step in solving circuit problems. If there is no voltage or the voltage is too low or high, before further inspection, the power supply issue must be resolved first.
The waveform of AC voltage may be sinusoidal (sine wave) or non sinusoidal (sawtooth wave, square wave, etc.). Many digital multimeters can display the RMS (effective value) of AC voltage. The effective value is the value at which the AC voltage is equivalent to the DC voltage.
Many tables have the function of "average response", which can provide a valid value when inputting a pure sine wave. This type of meter cannot accurately measure the effective value of non sinusoidal waves. A digital multimeter with true RMS function can accurately measure the true RMS of non sinusoidal waves.
The ability of a digital multimeter to measure AC voltage is limited by the frequency of the measured signal. Most digital multimeters can accurately measure AC voltage from 50 Hz to 500 Hz. But the AC measurement bandwidth of a digital multimeter can reach several hundred kilohertz. For AC voltage and current, their frequency range should be consistent with the specifications of the digital multimeter.
1. Pengukuran daripada DC voltan
① Insert the black probe into the COM socket and the red probe into the V/Ω socket.
② Place the function switch in the DC voltage range of V - range, and connect the test probe to the power source to be tested (measure open circuit voltage) or the load (measure load voltage drop). The polarity of the terminal connected to the red probe will also be displayed on the display.
③ Check the reading and confirm the unit
Nota:
② If the display only shows "1", it indicates over range, and the function switch should be set to a higher range
③ "Do not measure voltages above 1000V. It is possible to display higher voltage values, but there is a risk of damaging internal circuits."
④ When measuring high voltage, extra attention should be paid to avoiding electric shock
2. Pengukuran daripada AC voltan
① Insert the black probe into the COM socket and the red probe into the V/Ω socket.
② Place the function switch in the range of AC voltage range V~, and connect the test pen to the tested power supply or load. The test connection diagram is the same as above. When measuring AC voltage, there is no polarity display.
