Product Selling Point:1. What is STEM DIY Soldering Kits with Christmas Tree Shape When Assembled, 3D Christmas Tree DIY Soldering Kit is designed to improve electronic users' knowledge and soldering skills and make their lives better!2. Good home decoration our 3D three color Christmas tree is made of 36pcs 3-color LED light, which will make bright, colorful, and romantic light in the dark space. It will be a great decoration in the room, especially at a festival (e.g. Christmas)!3. The small Christmas tree set is made up of two light board s and a base light board, it is made up of tree like shape, the LED light board in the shape of a tree board shows the same alternating flashing water, it has a very beautiful effect.4. Basic Parameter: DC 4.5V-5V working voltage, can be directly powered by 3 AA batteries or USB power adapter (comes with battery holder and USB cable);5. This set is perfect for practicing welding skills. It's a great choice for you to enjoy DIY moments as well as gifts for friends and family. Product Specification:Product Name: 3D Christmas Tree LED Electronic Learning Set. Size: 70mm*110mm. Color: Colorful Lights/Tri-color LightSupply Voltage: DC 9V. Weight: 70gOscillating circuit working principles:1. After the first charge, charge capacitor C1 and c4.2. Capacitors C2 and C3 will continue to charge.3. When transistor Q1 and Q4 are turned on at the same time, it discharges capacitor C1 and C4.4. Capacitors C2 and C3 are fully charged, transistor Q1 and Q4 will be closed, and at the same time recharge capacitor C1 and c4.5. Transistors Q2 and Q3 are turned on, and capacitor C2 and C3 will be discharged.6. By analogy, the flash speed is the frequency of oscillation, and the frequency is determined by the values of resistor R and capacitance C. Common problem:1. First of all, if the light does not light up after welding, it is not a problem with the quality of the light. You can use the 2032 button battery to test the LED before welding to see if the test voltage is 3.0-3.5V and the current is about 20ma. After welding 50 sets of tests, the causes of lamp failure include electrostatic damage to the electric soldering iron LED, welding and pressing damage to the LED, damage to the bending pin of the LED. In general, if all goes well, there are more than two lights that are not on and we can replace them with two or three additional lights that we have given. Beginners can buy more in the store! Thank you very much!2. The recommended welding sequence is to first weld the components bottom plate, and then weld the resistors of the tube plates A and B-LED-transistor-electrolytic capacitor. The LED on the top of the board is assembled and then welded.3. The value of the resistance should correspond to the value marked on the table.4. Pay attention to the positive and negative poles of the LED lamp, and the long pin is the positive pole. The welding time of the LED lamp is as short as possible to avoid burning the LED.5. The triode is connected according to the shape on the board.6. Pay attention to the positive and negative electrodes of the electrolytic capacitor, and the long pin is the positive electrode.7. Welding finish lamp panel can use 5v power supply for the first time received the plate are negative, as part of the test, to check whether the light is not bright, if the light is not on, check the welding phenomenon and damage, and then replace the lamp, If it is parallel with the diagram, because the six light is not on, check the six light welding short circuit phenomenon, If it is not clear, please check the whole circuit welding short circuit, welding, power supply and other problems.8. When assembling the lampboard and bottom plate, please pay attention to the positive and negative poles of the lampboard and bottom plate to respond one by one. If it's bad, it's hard to disassemble. Package Included: 1 set. Note:1. Please allow 1-2cm differences due to manual measurement.2. Due to the light and screen difference, the item's color may be slightly different from the pictures. Warranty Services: If you have any questions about our products, please feel free to , we will provide you with quality service and best solutions. Hi, guys, thank you for visiting my store. There are so many useful and cheap items in our store. Welcome to visit. I hope you have a nice day!