Description: These DIY soldering practice kits with Xmas tree shapes after assembly. There are 3-color RGB LEDs divided into four groups, and each group has different flashing frequencies, when four groups flash together, it looks like a small Christmas tree. These 3D Xmas tree assemble kits are not only creative gifts, beautiful decorations, but also electronic learning kits, designed to practice beginners' electronic knowledge and soldering skill, they are perfect for school basic electronic and STEM educational projects. It is made of high-quality wood and ABS material. The length of this DIY Christmas tree is 13.6cm, the width is 6cm and the height is 6cm. This STEM DIY learning kits with the Xmas tree shape after assembled, them are not only season gifts and decorations, but also soldering projects, designed for electronic lovers, students and beginners, to practice electronic knowledge and soldering skills. Item Name: DIY Christmas Tree Material: Wood, ABS Working Voltage: DC4.5-5v Power Supply Mode: 3 AA Batteries Or USB Charger Features: Easy to Operate, Durable, Flashing Size Details: A, LxWxH: 13.6cm x 6cm x 6cm/5.35" x 2.36" x 2.36"(Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Production Steps: Firstly, Solder CTR-30A circuit board (referred to as A board) 1. Solder 4 resistors (R1 R3 R5 R7) 2. Solder 3 resistors 3. Weld 3 triodes and adopt the horizontal installation method (with direction) 4. Weld 3 electrolytic capacitors and adopt the horizontal installation method (with direction) 5. Solder the red LEDs (with direction), the red LEDs are numbered D1~D6. 6. After folding the pins, insert the corresponding holes (pay attention to the installation direction) 7. The red LED is soldered (number D1~D6) 8. Solder the yellow LED (with direction), number D7~D12 9. Solder green LED (with direction), number D13~D18 At this point, the welding of plate A is completed. Next, solder the CTR-30B circuit board in the same direction, referred to as the B board. A board and B board have different installation positions of two components; (install according to the position on the component list) 1. R2 R6 resistors are installed in different positions 2. The installation positions of the red, green and yellow LEDs are different 10. After the welding of the A board and the B board is completed, you can power on and test whether the two boards can light up and flash normally. Boards A and B can flash normally before continuing with the next steps. 11. Solder CTR-30C circuit board, referred to as C board Solder 1 DC socket (with direction) 12. Weld 1 button switch (with direction) 13. A board and B board are combined (there are directions, the two boards refer to the positive and negative poles of the bottom plate), after the two positioning arrows are aligned, use a soldering iron to fix the two boards together. 14. Battery box and C board combination Battery box and C board combination A. Solder the battery box wires B. Fix the battery box with screws and nuts 15. The pre-assembled AB board and C board are combined (there is a direction, and the polarity of the power supply must be consistent) 16. Solder the top LED (with direction) Package Includes: 3 x Circuit Boards 12 x Resistors 1 x Data Cables 1 x Battery Case 37 x LED Lights