1. Look at the screen print: the screen print faces the screen print, usually the left is positive and the right is negative.
2. Look at the shapes on both ends: the convex end is positive and the flat bottom is negative.
3. Multimeter measurement: red and black test leads When a positive number is displayed, the red line is + and the black line is - When a negative number is displayed, the red test lead matches. to the - electrode, and the black line corresponds to the + electrode.
Although there are many types of vehicles, their structures are similar. It must be said that this is the result of standardization and the need for large-scale production lines. With the development of society, the progress of science and technology and the changes in demand, the appearance of railway vehicles has begun to change, especially the passenger compartments no longer have the same visages. However, their basic structure has not changed significantly, but the specific parts have more scientific and advanced structural design.
Generally speaking, the basic structure of a vehicle consists of five main parts: the body, the chassis, the running section, the hitch buffer device and the braking device .
The body is the part of the vehicle that is used to transport goods or passengers, and also provides the basis for the installation and connection of other vehicle components. The bodies of early vehicles were mainly made of wood, supplemented with steel plates, arch bars, etc. for reinforcement. Modern bodies are mainly steel structures or lightweight metal structures.