How to choose a digital multimeter
The accuracy of the digital multimeter directly affects the accuracy of the measurement results. When you get a digital multimeter, you should first analyze its accuracy technical indicators: one is to see if the accuracy of the meter can meet your requirements, and the second is to analyze the overall accuracy of the meter. For performance analysis, don’t think that a 4-digit digital multimeter must have higher measurement accuracy than a 3.5-digit multimeter. The measurement accuracy of a 4.5-digit multimeter with rough craftsmanship may be better than that of a well-crafted 3.5-digit multimeter. The owner has encountered such a watch: a DT9103 4½-digit digital multimeter produced by an unknown small factory. During the measurement process, the numbers jumped very strongly, and it did not meet the requirements of the technical indicators.
Appearance
A good digital multimeter can become a pleasing handicraft, and it should be as perfect as possible in terms of materials, injection molding process, circuit boards, protective covers and other components.
Check item
After getting a digital multimeter:
First of all, you should check whether the case is in good condition, whether the switches and buttons function normally and feel good.
Whether the toggle switch (measurement function selection) is flexible in rotation, suitable for damping, comfortable in hand, and whether the corresponding measurement function is normal.
Whether the LCD screen is clear, whether there are missing strokes, and the digital jump should be as small as possible.
Whether the buzzer can sound.
reference factor
If you can open the case, you can pay attention to the design of the circuit board, the selected components, installation and soldering level, etc. For a good digital multimeter, the design of the circuit board is very important. Some major manufacturers' watches will use a multi-layer circuit board layout to provide better shielding and electrical performance. The level of selected components determines the measurement accuracy of the digital multimeter. High-end digital multimeters often use SMD components to improve the accuracy and reduce the volume of the circuit board. The components in key parts are even screened. We won’t talk much about the welding level, as all electronics enthusiasts know about it (when it comes to welding level, you can open a digital multimeter of more than ten yuan to see it, and the products of the workshop are guaranteed to make you feel terrible).
When purchasing, you should also pay attention to some details, such as whether the safety protection, product warranty, test cable, user manual, etc. are complete.
Performance testing
When purchasing a digital multimeter, you can confirm the measurement function of the digital multimeter by measuring known quantities (such as resistance, capacitance, battery voltage, AC voltage, etc.) acceptance.
