Generally, a complete machine is composed of several printed circuit boards, which can be large or small. And the circuits contained on each printed circuit board are often drawn on a circuit diagram. So, a complete machine circuit diagram often consists of several block circuit diagrams. After understanding each block circuit diagram, you can understand the entire machineline diagramEach block circuit diagram contains one or several circuit systems, and the complexity of large block circuit diagrams is almost the same as that of general small and medium-sized screen TV circuit diagrams. Although the circuits are relatively complex and various circuit boards perform different functions, they have rules to follow and can be read according to certain methods.

In order to avoid detours when reading circuit diagrams, correct reading methods and processes should be applied. Generally, the method of peripheral encirclement and from the outside in is adopted. By adopting a combination of table and interior, front and back connections, and step-by-step breaking, it is possible to read all circuit diagrams more smoothly. The specific method and process of looking at the picture can be summarized in three sentences and three processes: starting from the periphery, selecting the right import; Open the gap and connect before and after; Difficult point analysis, put it at the end.

1. Intuitively start, choose the right import

That is to say, first look at the most intuitive and easy to read components and circuits at the edge of the circuit, as an import for reading images. A batch of circuits or integrated blocks can be found along the signal line inward (possibly in the opposite direction of the signal flow) by these peripheral identifiable components.

2. Open the gap and contact the front and back

There are some weak links in the internal recognition of any circuit diagram. The complexity and difficulty of each part of the circuit are always different, or the graphics and symbols of certain components are different from those of general components. These are internal weak links in reading the diagram and are easy to read links. They can be used as internal breaks for viewing the diagram. Being able to choose these places as breakthrough points for reading pictures, after opening the gaps, can quickly connect forward, backward, left, and right, and work together with the first step method to recognize many circuits.

As long as readers pay attention, there will always be many links within the circuit diagram that they have already understood. Seizing them can quickly open up the gaps in the diagram and develop deeper. The most intuitive and easy to read internal components are integrated circuits, especially those large-scale integrated circuits, which have more than 40 leads, with some reaching over 100. They are very eye-catching in the diagram, and draftsmen often place them in the center or prominent position of the circuit diagram. Then, by expanding outward around these integrated circuits, one can easily find many circuits. There is a prerequisite for using integrated circuits as internal punch requirements. It is necessary to know the specific models of these integrated circuits, their main functions, and the names and uses of their main pins. Otherwise, it will bring a lot of inconvenience to reading the diagram. Sometimes readers have already understood most of the integrated circuits, but may not be familiar with certain individual integrated circuits. Based on the composition block diagram and connections, they can still guess the function of the unknown integrated circuit.

There are also some easily recognizable and memorable contents in the circuit diagram, which can also serve as internal breaking points in the circuit. For example, the Chinese characters, foreign letters or abbreviations marked in the diagram, some important and easy to read graphic symbols of components, some adjustable resistors or potentiometers, etc. In order to conveniently and smoothly apply these breakthroughs, readers should understand the physical meanings of various foreign letters and abbreviations, have a certain foundation in foreign languages (usually English), and be familiar with some professional terms and their abbreviations commonly used in audiovisual equipment; Readers should understand the functions, parameters, and indicators of these components. Readers have a wider range of knowledge, which is beneficial for reading pictures. Readers should consciously recall some useful knowledge.

3. Difficult point analysis, put it at the end

After the above two steps of reading process, most of the content of the circuit diagram can be understood. However, there may still be some parts of the circuit that are not understood or not very understood. The third step can be specifically used to encircle and annihilate difficult points. This is the difficult part of looking at the picture, and also the final step of looking at the picture. Readers can break through difficult circuits through various methods or means.

On useful circuit diagrams, the difficult to understand aspects often manifest in two places: one is the signal flow processing process inside certain integrated circuits, which cannot be understood, resulting in the inability to understand the function of external leads; The other is some peripheral discrete component circuits, without understanding the purpose and significance of setting up the circuit, and without knowing the signal processing process. Regarding these difficult circuits, based on the overall block diagram, the functions and interconnections of each part of the circuit, and through logical analysis, probing the functions and signal flow analysis methods, it is always possible to understand these difficult circuits.

In fact, there is a lot of information that can be read and used on the circuit diagram. With the help of readers' induction, analysis, and research, they must be able to understand the entire diagram. Everyone's actual situation is different, and the methods of looking at pictures and making judgments may vary slightly. The process of looking at pictures is not fixed. Electronic technology is developing rapidly, and manufacturers often develop new circuits or circuits with new functions, even with unique circuit programs. Be able to sensitively complete the task of viewing images based on the basic ideas mentioned above.

Article sourced from Jiangmen single and double-sided circuit boardhttp://www.yonghongpcb.com