16 types of 126 components, 276 solder joints 1206 package soldering; 0805 package soldering; 0603 package soldering; 0402 package soldering water lamp circuit soldering; PCB ruler; PCB common packaging examples; PCB line width examples 1. Size: 89*58MM 2. Board thickness: 1.6mm 3. International standard plate, all pads are tinned, high-strength fireproof and anti-fall material, which can be disassembled and assembled repeatedly. 4. The design of the PCB board is reasonable, and the commonly used SMD components are used. 5. The 3 columns of components on the left and right are used to practice welding, and each column has a test point. 6. The circular circuit in the middle is a running water lamp circuit, which is composed of CD4017, NE555, and light-emitting diodes. It can work after the welding is correct. 7. There is a ruler on the back of the circuit, which is convenient for measuring components. There are PCB wire examples, which are convenient for PCB design and use. 8. The working voltage of the circuit is 4.5~12V.