How to determine parameters and types step by step when selecting electronic components?

Crystal oscillators are used in more and more communication devices, and with the development of technology, the types of quartz crystal oscillators are also increasing, so many users are concerned about how to choose the parameters and types of crystal oscillators. Let's talk about three directions to determine your... Crystal type.

The importance of electronic component selection

Electronic components are the basic units of circuits that perform predetermined functions without being disassembled and decomposed, such as resistors, capacitors, semiconductor discrete components, semiconductor integrated circuit chips, microwave electronic components, relays, magnetic electronic components, switches, electrical connectors, filters, Sensors, fiber optics components, etc. According to practical experience, in electronic products, the failures caused by improper selection of electronic components account for 44%~67% of the total failures, while the failures caused by the product quality of the electronic components themselves account for only 33~46%, as shown in the following table. Therefore, the selection of electronic components occupies an important position in the circuit design, and the design staff must attach great importance, carefully estimate and plan carefully.

The size, specification and main parameters of each electronic component marked on the circuit are the basis for the selection of electronic components. For products that have already been formed, the electronic components on the circuit schematic diagram are put into production and processing after design, research and development, and trial products. The basic parameters are confirmed based on qualitative analysis, quantitative estimation, and experimental adjustment. Changes or changes are generally not permitted. However, for developers of electronic equipment, amateur enthusiasts, and maintenance staff, due to the influence of many factors such as objective reasons, under the condition of meeting technical standards and specifications, if the amount of use is small, electronic components can be selected flexibly. In some specified situations, even if the circuit schematic diagram is available, because some electronic components are not marked with complete basic parameters, such as electrolytic capacitors only marked with capacitance but not with withstand voltage, careful consideration must be given in the power supply circuit; product application field conditions and If the technical data does not match, you can change some electronic components to integrate into the actual environment; some electronic components are difficult to buy locally, you can choose the electronic components that meet the requirements; in the maintenance process, you find that an electronic component is unreasonable, you need to install it on the appropriate electronic components.

Criteria for selection of electronic components

1) Select standard electronic components produced by a promising and reputable manufacturer, and have been proven by practice to have stable quality and high reliability. Eliminated or inferior electronic components cannot be used.

2) The technical performance, quality grade and operating conditions of electronic components should meet the requirements of circuit design.

3) In the case of meeting the performance indicators, electronic components with low power consumption, low thermal resistance, low loss angle, high power gain and high efficiency should be selected.

4) Selection of domestic electronic components. Select the components that have passed the qualification certification and meet the national standards, the electronic components that have been practically tested, meet the regulations, and can be delivered stably, and other electronic components that have obtained successful application experience and meet the regulations.

5) Selection of imported electronic components: select PPL (preferred product list) and QPL (qualified spare parts list) from foreign authoritative departments, and high-reliability electronic components that have been strictly screened during processing; , comply with the regulations of high-quality electronic components.

6) Selection should be based on the principles of standardization and generalization.