Check the listing for details. 300 Elements DIY SMD SMT Welding Practice Soldering Skill Training Board. Condition: New. Listed at 15.68 USD. ☆ Welcome☆ to ☆ my ☆ shop ☆ Description: Highly Challenging.300 + SMD welding practice kits are the most difficult competition kits in Asian electronic welding skills competition.Professional Skills. complete this kit, need a certain professional knowledge base, practical training experience.High Quality Material.high-quality double-sided spray tin FR-4 circuit board, easy to solder, not easy to oxidize, contribute to success.Technical Support.need DC 9V power supply, component list, circuit diagram, principle description. Please contact us for information.Super Quantity Components.17 different types of electronic components. There are 1079 solder joints and 313 components. Product DetailsThis product is a set of electronic soldering exercise board kit, which needs to be soldered by yourselvesSuitable for electronic enthusiasts and major electronic vocational and technical school students soldering training study.Finished product displayThis kit contains 0805 packaged resistor, capacitor, SMD aluminum capacitor, SMD resistor, SMD crystal oscillator, SMD LED lamp, SMD diode, SOP14, SOP20, TQFP44 and other packaged SMD chips. There are 12 groups of SMD test areas. The welding difficulty is from low to high. Each group can be tested independently. It has short circuit and false soldering test functions. It can judge whether the welding is successful according to the display of LED lamp, A total of 314 SMD welding components are included. By welding, the welding ability, speed and circuit maintenance ability of various SMD components can be improved to meet the difficulty of the competition. With self inspection function, the welding results and welding errors can be seen after power on.Principle description:1. J1 and J2 are the power supply input terminals of the whole chip board, which can work normally when connected with AC6v. When it works normally, all the LED lights of the kit can work normally. At first, each group of LED flashes in running water, and then flashes at intervals. Finally, all the LED lights are on, and then flashes. This cycle is used to check whether the LED works and whether the LED is welded well. If the corresponding LED does not flash, it indicates that there is an error or false welding.2. AC9V power supply is rectified by D1-D4 diode, and then goes through each filter capacitor to the 1 pin of voltage regulator chip 78M05 (LED97 is always on, the rectifier circuit works normally), and outputs DC5V through 3 pins to supply the whole test circuit.3. The test circuit is controlled by a single chip microcomputer 12 groups of 8-bit LED lamp work. Each group is composed of one 74HC573 and 74HC164. A group can control 8 LEDs, a total of 12 groups. When it works normally, all the LEDs are on and can flash.Front and back of PCBProduct name: SMD soldering practice test kitPCB material: fr-4pcb boardPCB size: 146 * 100 mmThe color: the board is green and whiteProduct weight: 62gPower supply: mode DC 9VApplicable : All those who want to practice and learn how to solderNumber of solder joints: 1079Number of components: 314Data element list: circuit diagram, principle descriptionThe circuit principle diagramKit list and corresponding soldering position Package included:1pcs 300 Elements DIY SMD SMT Welding Practice Soldering Skill Training Board Shipping> We ship to worldwide.> Orders processed within 24-48 hours after payment verification.> We only ship to confirmed Paypal addresses. 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