This article introduces the testing methods and screening techniques of electronic circuit components

Date：2022-11-22 18:26:15 Views：855

It is reported that conventional electronic components need to be screened twice to meet the precision requirements of high-end industries such as aerospace, military and high-precision electronic products. At present, most of the first screening business is completed by the manufacturers themselves, and various professional testing institutions mainly undertake the second screening business. The components and parts shall be selected in a comprehensive way, reasonably selected according to favorable conditions, simplified circuit design to improve reliability, and derated use to improve reliability.

1、 Check the appearance quality

This is a simple and feasible inspection method, which can find the early defects of some electronic components and damages in the procurement process. The identification and detection of electronic components shall be carried out as follows:

1) The model, specification, manufacturer and place of origin of components shall be checked to ensure that they conform to the design requirements and the external packaging is intact.

2) Check the appearance of components and parts to ensure that they are in good condition, and the surface is free of defects such as dents, scratches and cracks. Components and parts with coating on the outside must be free of falling off and scratches.

3) The electrode leads of components shall be free of crimping and bending, and the coating shall be intact, smooth and free of oxidation and rust.

4) The model and specification marks on the components shall be clear and complete, the color code position and color shall meet the standards, and the characters on the integrated circuit shall be carefully checked.

5) The size of components of mechanical structure shall be qualified, the thread shall be flexible, and the rotation feel shall be appropriate.

6) Switch components can be operated flexibly with good hand feel; The tightness of connectors shall be appropriate and the contact shall be good. The components in various electronic products have their own characteristics, and the inspection contents shall be determined according to the specific requirements of each component.

2、 Electrical performance screening

In order to ensure the stability and reliability of electronic products, it is an important link to screen the components of the computer. During screening, one or more stresses shall be applied to electronic components to expose their defects and eliminate early failure according to the use requirements of components. The screening test and applied stress shall be within the appropriate range to make the defective components invalid, and the components with good quality will pass the test.

1. Component efficiency curve

The efficiency curve of electronic components, namely bathtub curve, reflects the failure rule of components in use. Generally, when the components are just put into use, the failure rate will be high due to the defects of raw materials, equipment, process, etc. in the component manufacturing process. After the components are used for a period of time, the failure rate of components is low, that is, the accidental failure period.

After the normal service life, the components enter the aging failure period, that is, the loss failure period. When the working life of the components ends in the aging failure period, the failure rate of the components increases.

2. Screening and aging of electronic components

The aging screening of components and parts shall be conducted under the early working conditions of artificial manufacturing components and parts, so that the components and parts are in the simulated working voltage state, and the products with early failure are eliminated before use, so as to improve the reliability of the products. In the production process, screening aging includes high temperature storage aging, high and low temperature cycle aging, high and low temperature impact aging and high temperature power aging. With the improvement of component production level, different aging screening requirements and processes should be selected according to different product requirements by the country and enterprises.

For typical components used in electronic products or equipment with high reliability requirements, 100% screening is required; For components used in civilian products with low requirements, sampling inspection shall be adopted; For the components used in the development and manufacture of general electronic products, natural aging and simple electrical aging shall be adopted.

3. Parameter performance test

After appearance inspection and aging of electronic components, performance indicators shall be tested to eliminate the failed components. Before testing, we should have a comprehensive understanding of common problems and solutions in the testing of electronic components.

It is required to have a variety of general or special test instruments. For general electronic design or components used in electronic equipment, universal meters and other general instruments shall be used for testing. When using a multimeter for testing, pay attention to the use requirements of the multimeter and use it correctly.

1) General multimeter has analog pointer type and digital type. The former is reliable, durable and intuitive, but the reading is inaccurate and the resolution is low; The latter has accurate and intuitive readings, high input resistance and high requirements for use and maintenance.

2) When using the two kinds of multimeter, it is required to select the function and jack: the pointer type generally has a special jack when measuring large current and high voltage; Digital meters use special jacks for measuring current above 200mA, and some models of multimeter use special jacks for current shields.

3) When selecting the measuring range, pay attention to the small error of pointer multimeter indication at about 30%~35% and 65%~70% of the full scale. If the measured range is not easy to determine, it is necessary to gradually convert from the maximum range.

4) When using the multimeter, the human body should not touch the metal part of the probe to ensure accurate measurement and personal safety.

5) When measuring high voltage or large current, do not shift gears during measurement. When shifting gears, disconnect the probe, select the range and connect the probe for measurement, otherwise the multimeter will be damaged.

6) When measuring polar components such as diode and rectifier, triode, aluminum electrolytic capacitor, pay attention to the polarity of the probe. In the resistance gear, the red probe of the pointer multimeter is connected to the negative pole of the internal power supply of the multimeter, the black probe is connected to the positive pole of the internal power supply, the red probe of the digital multimeter is connected to the positive pole of the internal power supply of the multimeter, and the black probe is connected to the negative pole of the internal power supply.

When the multimeter cannot meet the test requirements, LRC hand-held bridge shall be selected to measure the resistance, capacitance, inductance, quality factor and other parameters, and a combined multimeter shall be selected to measure the voltage, current, resistance, frequency and other parameters. Handheld bridge and desktop multimeter are selected to measure relevant parameters. The test accuracy is higher than that of the multimeter, and the measurement function that the multimeter does not have is still available.

The above contents are related to the detection methods and screening technologies of electronic circuit components compiled by the core creation detection team. I hope they can help you. Chuangxin Testing is a professional testing agency for electronic components. At present, it mainly provides integrated circuit testing services such as capacitance, resistance, connector, MCU, CPLD, FPGA, DSP, etc. Specializing in electronic component function testing, electronic component incoming appearance testing, electronic component dissection testing, acetone testing, electronic component X-ray scanning testing, ROHS component analysis testing. Welcome to call, we will serve you wholeheartedly!