Disassembly
The appearance is quite designed, compact, and has a bit of weight, heavier than the previous two.
There is a stand at the back.
Remove the plastic cover; the plastic cover serves to decorate and secure the front and back panels.
The battery cover has a screw; remove it.
Remove the two screws on the front and back panels to see the PCB.
Analysis
Now let’s analyze the PCB and the internals.
The conductive plastic strip for the LCD is designed to fit snugly, eliminating assembly positioning issues, and has a fixed barrier, which is more reasonable than the designs of the previous two.
The copper manganese wire used as a sampling resistor for the high current range shows signs of adjustment, indicating it has been calibrated. This is a detail that only a legitimate manufacturer would have, unlike typical counterfeit products.
It has the necessary fuses, and they are marked with voltage and current ratings.
It also has the required safety capacitors.
Buzzer.
The main control chip is a Niu Shi chip.
Rotary potentiometer, adjusts the reference voltage.
The critical power-related resistors are also using color ring resistors for power matching, and the necessary diodes are present.
Operational amplifier LM358.
Position contacts, 5 contacts.
You can see that there are spring balls, which press against the knob and contacts, ensuring good contact and sliding properties.
Two button sections.
Details of the LCD conductive strip section, with fixed barriers and left-right limits.
Removing the front fixed barrier of the LCD conductive strip.
There is an exposed antenna here, which should be used for wirelessly detecting whether AC power is present.
NCV is the abbreviation 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 the operational amplifier.
Conclusion
By comparing with the previous two multimeters, it can be seen that products from legitimate manufacturers are much more standardized in terms of safety, structure, and functionality, and they pay attention to many details.
1. Better structural design, including assembly compatibility, etc., for example, the LCD conductive strip not only has limits but also a fixed barrier.
2. Greater safety assurance, such as the selection of fuses, power resistors, safety capacitors, and the design of the PCB.
3. Assurance of functional performance, such as the copper manganese wire’s resistance being calibrated.
4. Added functionality for detecting the presence of voltage, namely NCV.
Overall, it is best to choose multimeters from legitimate manufacturers; those cheap counterfeit models that are given away in promotions are not recommended for safety and performance considerations, especially for high voltage and high current applications.
END