The TJ-56-516 new glass fiber tin-spray soldering practice board kit is improved based on years of professional teaching and competition practice, and the design of the circuit board is novel and scientific. The PCB board is made of high-quality glass fiber board, and the whole process of the large factory is sprayed with tin. The quality is excellent, and the design is optimized for practical training. It is suitable for training in electronic assembly skill competitions, continuously improving the welding process and speed, and can also be used in an electronic assembly competition.

Features:

• Interesting - After the circuit is installed, add 3-12V power to form a 10-channel running water lamp, which is novel and fun.

• Training - There are 149 components and 444 solder joints, which is convenient for training speed.

• Comprehensiveness - The circuit has 10 types of commonly used patch components, and can be familiar with using more components.

• Practicality - The circuit has a specific function, like electronic work.

• Savings - Can be used repeatedly after desoldering to increase the utilization rate.

• Flexibility - Each component has a number and no parameters so that the parameters can be adjusted flexibly.

• Intelligence - The circuit can intelligently judge whether the welding is normal when the circuit is powered on.

• Technicality - The circuit has a unique working principle, provides a complete schematic diagram, has test points, and can set up fault tests, which is convenient for various tests and is conducive to improving the theoretical level.

Product parameters:

Kit Name: Full SMD Soldering Practice Board

Board size: 70*57mm

Board thickness: 1.6mm

SMD components: 149

Welding spot: 444

Power supply: DC5V DC

Board material: FR-4 tin-plated, international standard plate, blue solder mask, all pads are tin-plated,

High-strength fireproof and drop-proof material, which can be disassembled and assembled repeatedly.

Principle description:

After the patch practice welding is completed, it can be used as a running water lamp to detect the effect of welding. When the power is first turned on because the voltage at both ends of the capacitors C1-C9 cannot change abruptly, pin 2 of the NE555 is at a low level, so pin 3 of the output terminal is at a high level, when the power is charged to C1-C9 through R61-R70 and PR1-PR5 When the power supply voltage is 2/3, the level of pin 3 of the output terminal changes from high to low, the internal discharge tube of NE555 is turned on. The capacitors C1-C9 are discharged through pin 7 of NE555 until the voltage at both ends of C1-C9 is lower than 1/3 of the power supply voltage. At this time, the level of pin 3 of NE555 changes from a low to a high level again, and C1-C9 is charged again, so the cycle forms an oscillation. Changing the resistance value of PR1-PR5 can change the oscillator's output frequency. The clock oscillation signal of NE555 is continuously added to the 14th pin of CD4017, and 10 transistors are connected to the 10 output terminals of CD4017 to drive 10 LEDs. When the 10 output terminals of CD4017 generate high levels in turn under the action of the clock signal, L1-L10 are lit up in turn, thus forming the effect of running water lights.

Attention when soldering: 

SMD components are relatively small, and be careful not to lose them. LEDs, diodes, and chips all have directions. You must pay attention to welding!! The green dot of the LED is the negative pole. You can use the diode gear of the multimeter to light up the LED. The red pen is positive, and the black end of the diode is negative. When supplying power, connect the positive pole of the power supply to +, the negative pole to -, and the power supply voltage is 5V.

Components list:

① Resistors --- packaged as 0805 (50 pieces)

② Resistors --- packaged as 0603 (10 pieces)

③ Light-emitting diodes --- packaged as 0805 (10 pieces)

④ Array resistors --- packaged as 0603 (5 pieces)

⑤ Capacitors --- packaged as 0805 (10 pieces)

⑥ Diodes - packaged as 1206 (10 pieces)

⑦ Transistors - packaged as SOT-23 (10 pieces)

⑧ Integrated chip type--packaged as SOP-8, SOP-16 (2 pieces)

⑨ Resistor or capacitor --- Package is 0402 (10 pieces)

⑩ Integrated chips--encapsulated as LQFP44 (2 pieces)

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