• Product Use

This is because the input impedance for mV measurement is high, typically at a level of GΩ. When the test leads are open, the induced voltage from ambient electromagnetic waves can easily be detected by the multimeter, especially during mA DC or mV AC measurements. Therefore, it is normal that the displayed value cannot be reset. The displayed value can be reset if the test leads are shorted.

The accuracy is typically denoted in the percentage form of the reading, that is 1% of the reading, for example, if the measured value is 100V, the actual value may be between 99V~101V. But for technical parameters, the least significant digit will be counted into the accuracy, for example, if the accuracy is ±(1%+2) and the measured voltage is 100V, the actual value will lie between 99.8 and 101.2V.

True-RMS Measurement: The value of the AC signal is obtained using the root mean square algorithm. It accurately measures the effective value of the signal, regardless of waveform distortion.
Average Response Measurement: The average value is multiplied by the waveform factor to obtain the value of the AC signal. It is only accurate for pure sine waves. For distorted waveforms or non-sine waves (such as square waves, triangular waves, sawtooth waves), only True-RMS can provide accurate measurements.

The transistor (Q1) on the PCB may be damaged. Please send the product to the manufacturer for maintenance.

1. Check if the USB function is started (There is symbol indication on the LCD)
2. Check if the software version supports the operating system.
3. Connect with other computers to check if the operating system is incompatible with the software.

Poor contact of conductive adhesive at LCD screen due to impact or bumping. (Apply new conductive adhesive or send the product to the manufacturer for maintenance)

The multimeter is protected by a fuse at the current gear. It is also protected at the voltage gear, as it can detect voltages up to 1000V and is designed with an internal resistance of 10MΩ. There is no fuse protection at the resistance gear because a voltage excitation source exists at this gear. The measured resistance is detected by measuring the current flowing through it. If voltage is measured at the resistance gear, two voltage sources may clash, potentially damaging the multimeter. An overload-protection circuit is also designed into the multimeter.

The copper wire of the test lead may be broken, please replace the test lead with new one. Note: Do not twist the test leads.

Generally, the specification of frequency accuracy is applicable to above 5% or 10% of the range, if below 5% or 10%, the accuracy will be affected, the affected value and the starting value of the range changes upon the models of products. For nonsinusoidal waveform measurement, please select a True-RMS meter and be sure that the range of duty cycle is 1%~99%.

It is generally difficult for a multimeter to detect noise or spike signals in an AC signal, as the multimeter detects the value at a specific time point. When converting digital to analogue, the sampling point may not capture the peak of the noise, so the test result may not reflect the presence of noise in the waveform signal. In contrast, an oscilloscope captures a continuous waveform and can capture MAX/MIN values through oversampling, thus displaying the noise signal.

The MCU control chip is damaged, please send the multimeter to manufacturer for maintenance.

Because the air is moist and the moisture content in the vaseline applied on the PCB pad increases. Please wipe out the vaseline on the PCB pad and apply new vaseline, or perform measurement when the air is dry.