Date：2022-03-28 14:50:52

Under the action of external load, the metal breaks when the stress reaches the breaking strength of the material. The fracture process of metal materials generally has three stages: crack initiation, crack metastable propagation and unstable propagation, and finally fracture. Metal components may crack and initiate cracks under different conditions in material manufacturing, component forming or use stages; Under the influence of different environmental factors and bearing state, the crack propagates until fracture. View >>

Date：2022-03-28 14:38:08

When mechanical parts lose their working capacity or fail to meet the design requirements for some reasons, it is called failure. The failure of mechanical parts does not simply mean damage, which can be summarized into three situations: completely unable to work; Although it can work, its performance is poor and exceeds the specified index; Serious injury and loss of ability to work safely. In order to prevent the failure of parts, it is necessary to analyze the failure of parts, that is, by judging the failure form of parts, determining the failure mechanism and causes of parts, selecting materials pertinently, determining reasonable processing routes, and putting forward failure prevention measures. View >>

Date：2022-03-28 14:29:30

Capacitor is an indispensable part of circuit or power equipment. And there are many kinds of capacitors, ceramic capacitor is one of them. The reason why the capacitor will leak electricity is that the dielectric material between the two poles of the capacitor cannot be absolutely insulated, but can only be relatively insulated. Therefore, there is leakage current in some capacitors. View >>

Date：2022-03-28 14:26:27

Field effect transistor is abbreviated as FET, which can be divided into junction field effect transistor (JFET) and insulated gate field effect transistor (MOSFET). We usually call it MOS transistor for short. The MOS tube can be divided into enhanced and depleted, and the enhanced MOS tube is commonly used in our common motherboard. FET is a voltage controlled semiconductor device in which most carriers participate in conduction. It has the advantages of high input resistance (107 ~ 1015 Ω), low noise, low power consumption, large dynamic range, easy integration, no secondary breakdown phenomenon, wide safe working area and so on. It has become a strong competitor of bipolar transistor and power transistor. View >>

Date：2022-03-25 15:14:58

The basic principle of performance testing is: the earlier the problem is found, the easier it is to locate the problem and repair the problem. Therefore, performance testing can run through all stages of the software development life cycle. For example, unit testing can test the functional accuracy under multithreading concurrency, each API also needs to be tested and evaluated, the data size and cache usage of the modules used need to be taken into account in the integration test, and the relevant global performance indicators need to be measured from the perspective of user load in the system test. So, when will performance testing be carried out? What is the purpose of performance testing? View >>

Date：2022-03-25 15:08:27

Any task must first confirm the goal of the task. If you don't know the goal, the result of any effort may not be the final desired result. The same is true of performance test. In the past, although testers have been serious and responsible for the test work from beginning to end, after the test report is released, everyone always feels that there are deficiencies in the United States and has doubts about the test results, especially in the performance comparison test for different test objects with a long time span, there are more or less the following problems: View >>

Date：2022-03-25 15:01:00

Micro controller unit (MCU), also known as single chip microcomputer or single chip microcomputer, is to appropriately reduce the frequency and specification of central process unit (CPU), and integrate peripheral interfaces such as memory, counter, USB, a / D conversion, UART, PLC, DMA and even LCD drive circuit on a single chip to form a chip level computer, Do different combination control for different applications. View >>

Date：2022-03-24 16:10:40

What kind of certification does CNAs certification belong to? CNAs (full English Name: China National Accreditation Service for conformity assessment) is the abbreviation of China National Accreditation Commission for conformity assessment. It is a national accreditation institution authorized by the state administrative department. It is responsible for the accreditation of testing qualifications of relevant laboratories and testing institutions, and granting CNAs testing qualifications to institutions or laboratories that meet the testing environment and testing ability. View >>

Date：2022-03-24 16:08:05

CNAs accreditation is the abbreviation of China National Accreditation Service for conformity assessment (CNAs). It is a laboratory combined and reorganized on the basis of the former China National Accreditation Service (CNAB) and China National Accreditation Commission for laboratories (CNAL). The laboratory has obtained the CNAs Accreditation Mark and its ability has been recognized by the national accreditation organization, The report with approval mark can be issued to facilitate business. View >>

Date：2022-03-24 15:59:34

CNAs accreditation is an activity carried out by China conformity assessment Accreditation Committee and belongs to the voluntary accreditation system. Any third-party laboratory can apply for accreditation based on the report issued by the accredited laboratory. China National Laboratory Accreditation Committee (CNAs) and International Laboratory Accreditation Cooperation Organization (ILAC) can be used; Obtain the recognition of the national and regional accreditation institutions of the parties to the mutual recognition agreement. Having CNAs certification means that the organization has been certified by China National Accreditation Commission for conformity assessment and has the technical ability to carry out testing and calibration services in accordance with relevant international recognized standards. View >>