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Disassembly
The appearance is quite stylish, compact, and has a solid feel, heavier than the previous two models.
There is a stand at the back.
After removing the plastic casing, it serves both decorative and structural purposes for fixing the front and back panels.
The battery cover has a screw to be removed.
Remove the two screws from the front and back panels to see the PCB.
Analysis
Now let’s analyze the PCB and the internal components.
The conductive plastic strip for the LCD is designed to fit snugly, eliminating the need to consider assembly positioning issues, and it has a fixed baffle, which is more reasonable than the designs of the previous two models.
The copper-manganese wire used for the high current range serves as a sampling resistor, and there are signs of adjustment, indicating it has been calibrated. This attention to detail is typical of legitimate manufacturers, unlike generic products.
It has the necessary fuses, clearly labeled with voltage and current ratings.
It also includes the required safety capacitors.
Buzzer
The main control chip is a high-quality chip.
Rotary potentiometer to adjust reference voltage.
The critical power-related resistors are also using color-coded resistors, ensuring proper power matching, and the necessary diodes are present.
Operational amplifier LM358
Switch contacts, 5 contacts.
It can be seen that there are spring balls, which press against the knob and contacts, ensuring good contact and sliding.
Two button sections.
Details of the conductive strip for the LCD, with fixed baffles and lateral limits.
The conductive strip for the LCD has the front fixed baffle removed.
There is a bare antenna here, which should be used for wirelessly detecting whether AC voltage is present.
NCV stands for Non-Contact Voltage, which uses electromagnetic or electric field induction principles to determine the presence of voltage. The aforementioned wire is used for this purpose, and the signal is amplified through an operational amplifier.
Conclusion
Comparing with the previous two multimeters, we can see that products from legitimate manufacturers are much more standardized in terms of safety, structure, and functionality, with greater attention to detail.
1. The structural design is better, including assembly compatibility, for example, the LCD conductive strip has both limits and a fixed baffle.
2. Safety is better ensured, such as the selection of fuses, power resistors, safety capacitors, and PCB design.
3. Functional performance is also guaranteed, such as the calibrated resistance values of the copper-manganese wire.
4. It includes the added functionality of non-contact voltage detection, NCV.
Overall, it is advisable to choose multimeters from legitimate manufacturers. Those promotional, very cheap counterfeit products should be avoided for safety and performance reasons, especially when dealing with high voltage and high current.