Things to keep in mind when buying a multimeter
A. Accuracy
The precision of digital multimeter directly affects the accuracy of measurement results, get a digital multimeter should firstly analyse its precision technical indexes: firstly, to see whether the precision of this piece of table can reach their requirements, secondly, to analyse the overall performance of this piece of table, don't think that a 4-digit digital multimeter must have a higher precision than a 3.5-digit digital multimeter, a piece of rough process of 4.5-digit digital multimeter may also catch up with a piece of well-made 3.5-digit digital multimeter. The measurement accuracy of a rough 4.5-digit digital multimeter may also catch up with a well-made 3.5-digit digital multimeter. The owner of the shop has encountered such a table: a 4.5-digit digital multimeter generated by a nameless small factory, the number jumps very much in the process of measurement, and it is not at all down to the requirements of the technical specifications.
B. Notes
Appearance
A good digital multimeter can become a pleasing craft, whether from the material, injection moulding process or circuit board, protective cover and other parts, should be as far as possible to do **.
Second, the main check items
After getting a digital multimeter:
First of all, you should check whether its case is intact, switches, buttons are functioning properly, feel good.
Toggle switch (measurement function selection) whether the rotation is flexible, damping is appropriate, feel comfortable, corresponding to the measurement of the measurement function is normal.
Whether the liquid crystal display is clear, there is no missing strokes, the digital jump should be as small as possible.
Whether the buzzer can sound.
Third, other reference factors
If you can open the case, you can pay attention to the design of the circuit board, selected components, installation and welding level, etc., a good digital multimeter, the circuit board design is very important, the domestic table is generally a double-layer board, while some foreign manufacturers will choose a multi-layer layout of the circuit board to provide better shielding and electrical performance. The level of selected components determines the measurement accuracy of the digital multimeter, digital multimeter often use SMD components to improve accuracy while also reducing the size of the circuit board, the key parts of the components will even be screened. Welding level is not much to say, electronic enthusiasts know (speaking of welding level, you can open a piece of a dozen dollars of digital multimeter to see, handmade workshop products are guaranteed to make you feel miserable).
In addition to purchase should also pay attention to some details, such as protection, product warranty, test cables, user manuals, etc. are complete.
Fourth, performance testing
Purchase of digital multimeter, you can measure known quantities with the help of methods (such as resistance, capacitance, battery voltage, AC voltage, etc.) on the digital multimeter measurement function to confirm that the conditions can be sent to the appropriate agencies on the technical indicators of the item-by-item inspection, acceptance.
Finally, I have to say: digital multimeter from flying into the common people's home is just a matter of nearly 10 years, but due to fierce competition, many domestic manufacturers to spell the results of the price, resulting in recent years the overall quality of the domestic digital multimeter level is not high, so when choosing, we must pay more attention, after all, a good table can be accompanied by a lifetime.
