Development and current situation of safety testin

The development and current situation of electronic product safety testing instruments

I. the safe use of electronic products

with the rapid development of science and technology, people's living habits have changed greatly with the continuous improvement of living standards. Electronic products have gradually entered the family, from electric fans to air conditioners, from black-and-white TVs to color TVs, from single cylinder washing machines to fully automatic washing machines, and so on. Electronic products gradually liberate people from heavy physical labor. People are increasingly dependent on these electronic products. Whether we are aware of the potential safety hazards when using these electronic products to bring us infinite happiness. Fire accidents often occur. Electric leakage of electronic products will also directly endanger personal safety. Electromagnetic radiation of electronic products will affect people's health. The existence of these potential safety hazards has aroused widespread concern of countries and relevant international organizations all over the world. Measures have been taken to strengthen the formulation of electrical safety standards and relevant regulations. And include it as an important part of the market access system. Such as IEC standard of International Electrotechnical Commission. American UC standard, German GS standard, etc. China started relatively late in this regard, and developed rapidly after China joined the "IEC organization for testing and certification of electrical products of the International Electrotechnical Commission" in 1985. The standards of various products are close to IEC, especially the implementation of the "standardization law of the people's Republic of China". It is legally guaranteed. The standardization law stipulates: national standards, industrial standards, mandatory standards and recommended standards respectively. Mandatory standards must be implemented. Products that do not meet the mandatory standards are prohibited from production, sale and import. The State encourages enterprises to voluntarily adopt recommended standards

two, at present, China's relatively popular experimental power several safety standards

after the reform and opening up, China's home appliance industry has first developed rapidly, and the related "safety of household and similar electrical appliances" standards GB4706 and IEC standards have also been implemented earlier. The medical industry has also developed rapidly in recent years. The relevant standards include the general safety requirements for medical electrical equipment "gb9706. (IEC)" and the audio and video industry. There are "safety requirements for audio, video and similar electronic equipment" GB, (iec60065:1998); The information industry has "security of information technology equipment" gb/(IEC); General safety requirements and tests of lamps and lanterns. The lamp industry has gb7000.1 (IEC); The mechanical industry has "mechanical safety mechanical electrical equipment" (gb5226./iec:2000), etc

a common requirement of these safety standards is that the product must meet the four mandatory tests of "voltage withstand test", "insulation resistance test", "contact resistance test" and "leakage current test". As long as one of the tests does not meet the standard requirements, the product will be judged as unqualified and will not be allowed to enter the market

III. safety tester (safety regulation instrument)

electric shock prevention of electronic products is the most important and basic of all safety standards. 8. Clamping diameter of round specimen: φ 6 ⑵ 6mm this requirement. With the development of household appliances and other industries in China, instruments and equipment for basic safety test of various special electronic products have developed rapidly. A brand-new category of electronic instruments and equipment has been formed, namely safety tester (safety regulation tester)

1, voltage withstand tester

voltage withstand tester, also known as dielectric breakdown device, insulation strength tester, high voltage tester, high voltage breakdown device, voltage withstand tester, etc. Basic requirements of withstand voltage tester:

test voltage display - pointer or digital display

leakage current display - pointer or digital display

test time display - generally s

boost form - automatic or manual

breakdown alarm current can be set to full range

alarm form sound and light

error is generally within ± 5%

2. Leakage current tester

the latest version of the standard, The leakage current test has been changed to contact current test. These two names have the following two differences:

① there are differences between human simulated impedance networks

in the 4706.1 standard, there is only one human simulated impedance network. The latest version of the standard: the human body analog impedance network refers to figure 3 and Figure 4 of GB (iec990:1990). These two networks are different

② the frequency response requirements are different

the new standard requires the frequency to be 1MHz. Originally, only 5KHz was required. In fact, the frequency response requirements of the amplifier have been improved. Leakage current (contact current, a strong fortress to deal with market changes) test is required to be tested under the condition of adding working power supply. Therefore, there are two kinds of leakage current (contact current) testers. A kind of passive tester - the working power supply of the tested equipment is not provided by the tester, and an additional power supply must be added. The other is the active tester - the working power supply of the tested equipment is provided by the tester. So the tester should have a meaning of output power

3. Insulation resistance tester (also known as megger)

insulation resistance tester is used to measure insulation resistance. Basic requirements:

test voltage 500v/dc1000v/dc two gears

test range m Ω or 1000m Ω direct measurement method is a method specially used to measure the wear of a certain working surface

4. Grounding resistance tester

also known as contact resistance tester, grounding impedance tester. Basic requirements:

test voltage, AC, DC optional. The measured voltage is less than or equal to 12V, but there are also not more than 6V (9706 medical standard). The test current is generally 10a, 25A, etc. The instrument is required to output a current

note: the following topics are the basic principle, use and calibration method of voltage withstand tester and insulation resistance tester