The circuit board is mainly composed of pads, vias, mounting holes, wires, components, connectors, filling, electrical boundaries, etc. The circuit board makes the circuit miniaturized and intuitive, which plays an important role in the mass production of fixed circuits and optimizing the layout of electrical appliances. The circuit board can be called a printed circuit board or a printed circuit board. The export of circuit boards to the EU requires environmental ROHS testing.

RoHS certification is also called environmental certification, which is in line with European and American standards. It is the abbreviation of \"The restriction of the use of certain hazardous substances in electrical and electronic equipment\" (The restriction of the use of certain hazardous substances in electrical and electronic equipment). It stipulates that if lead, Pb, Imports of harmful heavy metals such as cadmium Cd, mercury Hg, hexavalent chromium Cr6+, polybrominated diphenyl ethers PBDE and polybrominated biphenyls PBB have been banned by the EU from July 1, 2006.

With the widespread use of lithium batteries in mobile communications, electronic appliances and other fields, safety accidents caused by lithium battery explosions are not uncommon in recent years. You can often see in the news that lithium batteries explode or lithium batteries explode during battery charging while mobile phones are being charged. Safety accidents caused by fires, etc., so the battery performance test through the standard system is a way to solve whether the battery is safe and reliable.

The so-called quality inspection report refers to the safety and performance testing of the product, successfully entering other platforms such as Tmall, JD.com or supermarkets, or as a reference standard for consumers. According to the three-level standard (national standard, ministerial standard and enterprise\'s own standard), carry out quality assessment, make basic evaluation, and analyze the reasons for qualified or unqualified quality. This is the main part of the quality inspection report. It is necessary to have a laboratory authorized by China Metrology Certification (CMA) + China National Accreditation Service for Conformity Assessment (CNAS), and the quality inspection report issued by it is valid.

KC (Korea Certification) certification, formerly known as EK certification, is South Korea’s electrical and electronic appliance safety certification system, that is, KC mark certification. The Korea Institute of Technology Standards (KATS) was established in 2009 in accordance with the Electrical Appliances Safety Management Act (ELECTRIC APPLIANCES SAFETY CONTROL ACT). The compulsory safety certification system implemented on January 1, from January 1, 2011, 13 certification marks have been included in the national comprehensive certification mark KC.

RoHS is a directive issued by the European Union, which needs to be implemented after the member states are transformed into regulations; and the Reach regulations come into effect directly after the promulgation. Reach is the framework and RoHS is the specific directive.

PSE (Product Safety of Electrical Appliance & Materials) certification (called \"fitness inspection\" in Japanese) is a mandatory market access system for electrical appliances in Japan and an important content stipulated in the \"Electrical Appliance Safety Law\" in Japan. Electrical appliances are divided into \"specific electrical appliances\" and \"non-specific electrical appliances\", of which \"specific electrical appliances\" include 116 products; \"non-specific electrical appliances\" include 341 products, and technical requirements include EMC and safety.

TWS is the abbreviation of True Wireless Stereo in English, which means true wireless stereo. TWS technology is also based on the development of Bluetooth chip technology. According to its working principle, it means that the mobile phone connects to the main earphone, and then the main earphone quickly connects to the secondary earphone wirelessly, so as to realize the wireless separation of the left and right channels of Bluetooth. When the slave speaker is not connected, the main speaker returns to mono sound quality. TWS technology has been applied to the field of bluetooth headsets, so a new product-TWS bluetooth headset was born.