Principles and methods of selecting electronic components

发表于2020-04-01

  1. The component is the basic element of the circuit and the final result of the circuit principle analysis and calculation. In the circuit principle analysis, the structure, characteristics, parameters of each component, the role in the circuit and the impact on the whole circuit should be understood. In circuit parameter calculation, each component parameter is the final result of circuit calculation, so it is convenient and reasonable to choose the component specification and model.


    The correct selection of components is the key to realize the function of the circuit. The selection of components is based on standardization, generalization, and localization. Select the qualified components that meet the requirements of circuit parameters; The purpose is to use scientific methods to achieve the circuit design of selected components of the circuit technical indicators. Electronic components are the basic components of a circuit that cannot be disassembled or decomposed, such as resistors, capacitors, semiconductor discrete devices, semiconductor integrated circuits, microwave components, relays, magnetic components, switches, electrical connectors, filters, sensors, optical fiber equipment, etc. Practice has proved that in electronic equipment, faults caused by improper selection of components account for 44% ~ 67% of the total number of faults, while faults caused by the quality of components only account for 33-46%, as shown in the following table. Therefore, the choice of components plays an important role in the circuit design, the designer must attach great importance to, careful calculation, careful design. The specification, model number and parameters of each component indicated on the circuit are the basis for selecting the electronic component. For finished products, each component on the schematic diagram is put into production after design, development and trial production, and each parameter is determined by qualitative analysis, quantitative estimation and experimental adjustment. In general, it is not allowed to be replaced or changed. However, for the research and development of electronic products, amateurs, maintenance personnel, due to the objective conditions and many other factors, the technical requirements that meet the standard conditions, if the dosage is small, you can choose the components flexibly. In certain cases, even if there is a schematic diagram, the parameters of some components are not complete, for example, the electrolytic capacitor is only the standard capacity rather than the standard voltage value, so it should be reconsidered in the power supply circuit. If the field conditions used for the product are inconsistent with the technical data, some components can be adjusted to fit the actual environment. Some components can not be purchased locally, you can choose to meet the requirements of the components for replacement; A single component is found to be unreasonable during maintenance and the appropriate component needs to be replaced.


    Component selection principle


    1) choose standard components produced by promising and reputable manufacturers with stable quality and high reliability, such as shenzhen lianfengtai technology co., LTD


    2) the technical performance, quality level and use conditions of components should meet the requirements of circuit design.


    3) when performance parameters are met, components with low power consumption, low thermal resistance, low loss Angle, high power gain and high efficiency should be selected.


    4) optimize domestic components. Select components that are certified and meet national standards, pass actual tests, meet requirements and are reliably supplied, and other components that have successful application experience and meet requirements.