The definition of the circuit diagram

The schematic is also called the "electrical schematic." This kind of map, because it directly reflects the structure and working principle of the electronic circuit, it is generally used in designing and analyzing circuits. When analyzing the circuit, you can understand the actual operation of the circuit by identifying the symbols of the various circuit components drawn on the drawings and the connections between them. A schematic is a circuit case that embodies the working principle of an electronic circuit.

The PCB diagram is a mapping drawing of the circuit board. It describes the layout of the circuit board and the position of the components in detail.

Looking at the circuit diagram 

First of all, look at the power supply section to understand what the circuit is doing under the condition of the power supply, AC or DC, single or multiple power supply and voltage levels. After seeing the branch circuit clearly, the first difference is whether it is a digital circuit or an analog circuit. The analog circuit looks at the signal acquisition to find out the source of the signal. There are radio frequency, audio, various types of sensors, instrumentation, or other circuits. The analysis signal is exchange, DC or pulse, is a voltage type or current type. Analyze the function of the subsequent circuit and find out whether it is demodulation, amplification, shaping, or compensation. Finally look at the output circuit, whether it is modulation or drive. Digital circuits mainly analyze the logic functions and functions of the circuit.

To understand the circuit board, first of all it is best to be able to understand its electrical schematics (ie, circuit diagrams), to grasp the electronic components and the way it works, to master the normal parameters of some commonly used components and The knowledge of the role played in a normal circuit, and then the analysis of the circuit board (called a printed circuit board), can quickly understand its working principle and some situations that need to be mastered.

Molecular circuit module, and then find the core components of a sub-circuit (of course, be familiar with this component) to find out the electrical connection between the sub-circuit modules, and finally the entire circuit output and input or function.

The whole circuit has a certain function, which is composed of each unit circuit. The unit circuit constitutes a signal processing branch with certain functions, and then these branch circuits constitute the whole circuit. First of all, make sure what you see in the circuit diagram is what kind of circuit, is audio, video, digital, or hybrid circuit, and then use the corresponding unit circuit knowledge to interpret these circuits, and from the AC signal level Analysis of the DC level, the DC part of the circuit is the basis for the normal operation of the circuit, the AC signal can be processed after the DC circuit is normal, and the circuit does not have a good DC state and cannot work normally. Also from the frequency level, the gain level of the amplifier is analyzed. When the signals of different frequencies are processed by the circuit, due to the non-linear elements in the circuit, they will have different processing results for different frequencies. The amplifier also has different signals at different frequencies. With different amplifying capabilities, the circuit will perform targeted processing of the required frequency signal during design, so as to meet the needs of the machine function. Another is to analyze the relationship between the unit circuits, and the relationship between the input and output of the unit circuits. What happens to the AC signal after passing through these circuits? After understanding the working principle of each branch, the working principle of the whole machine can be analyzed. Sometimes there are cross-links between the branch circuits, for example, the line retrace pulse of the TV output circuit is used for color. The decoding circuit, the line output circuit and the color decoding circuit have signals that are connected to each other. At this time, these branches can be understood as another unit circuit, and then they are analyzed.

I think there is a sequence problem in this: For example, for high-frequency circuits, the function of the circuit and the relationship between the input and output should be mastered first. With overall assurance, it is like catching the nose, because although the circuit is different, the device is different, but Their input and output relationship spectrum will not change. Then analyze the basic principles and methods to achieve such functional transformation, specific to part of the analysis.

The circuit design is to start by analyzing the circuit schematic, but must first understand the pin and the basic role of the required chip, this will help to better understand the working principle of the circuit, so that it can be applied to its own circuit, is conducive to Circuit cutting and expansion. In the circuit analysis, first of all, there is an overall understanding of the circuit schematic, and divides each function module, such as power module, controller module, memory module, audio module, GPRS module and so on. Each module is analyzed one by one, and at the end of the process, the functions to be realized by the circuit can be generally understood. When designing a circuit, it is best to master the principles of common or commonly used unit circuits, such as power modules, voltage regulator modules, memory modules, etc., commonly used chips, such as: 7805, 7812, etc.

When designing a circuit, it is necessary to divide the circuit to be designed into several modules, so that they are designed in different schematics and finally integrated. When there is a signal input in the circuit, what is the voltage at each basic point and what the current is, there must be a rough estimate. For an amplifier, R, L, C circuit depends on whether it is an oscillation circuit, an amplification circuit, or a shaping circuit.

Transistor static operating point analysis, analysis of working conditions, etc., capacitor filtering, inter-stage coupling, high frequency, low frequency circuits, etc. Generally, we use low-frequency circuits, and high-frequency communications are generally used in communications.

After self-analysis and self-design, you will know and master the basic principles of the circuit, and have accumulated experience in design and debugging in your own design. Of course, real skills need to be tempered!