Skill training patch component welding practice board $ 6.45 Board size: 89*58MM Board thickness: 1.6mm International standard board, all solder pads are tin-plated, high-strength fireproof and anti-drop material, which can be disassembled repeatedly. The PCB board design is reasonable, and all commonly used SMD components are used. The left and right 3 columns of components are used to practice soldering, and each column has test points. The circuit in the middle circle is a water lamp circuit, which is composed of CD4017, NE555, and light-emitting diodes. It can work after the welding is correct. There is a ruler on the back of the circuit, which is convenient for measuring components. There are examples of PCB wires to facilitate PCB design and use. The working voltage of the circuit is 3~12V. This kit contains all the components on the following photos.