Comprehensive Welding Practice Board

I. Project Introduction:
JLCPCB EDA Integrated Soldering Practice Board includes through-hole and surface-mount packages of common basic components such as resistors, capacitors, and inductors. After completing the soldering of the required components (to achieve circuit functionality), it can realize the effects of running lights and breathing lights. The board provides packages such as 0805/0603/0402/0201/01005 for advanced challenges, comprehensively assessing the soldering skills of the user.
II. Principle Analysis:
After power-on, the slide switch is moved to the position closest to the Type-C terminal (ON). The DIP switches 1-7 from left to right control the on/off state of the through-hole running lights. The rightmost switch controls the on/off state of the 24 LED breathing lights in the upper right corner. The effects of running lights and breathing lights are controlled by lightly touching the buttons.
When the button is not pressed, the gate (G) of the PMOS transistor is pulled low by a 100KΩ pull-down resistor, keeping the PMOS transistor gate in a stable low-level initial state to prevent uncertain states caused by external interference. The PMOS transistor is turned on, and the LEDs are controlled to turn on and off by the DIP switches. When the button is pressed, the gate of the PMOS transistor is at a high level, the PMOS transistor is cut off and does not conduct, and the LED's running light or breathing light effect is activated. The button has higher priority than the DIP switch.
The Schottky diode is used to prevent current backflow.
2.1 Running Light Circuit
The running light effect is achieved by using an NE555 timer to construct a multivibrator to drive a CD4017 decimal counter. For
circuit principle details, please refer to the reference case: [DIY] Nanjing University North Building Memorial PCB
2.2 Breathing Light Circuit
The breathing light effect is achieved by using an LM358 operational amplifier and peripheral circuits to construct a triangular wave signal generator.
For circuit principle details, please refer to the reference case: [Analog Circuit] Simple Star Breathing Light
III. Component Soldering
3.1 Bill of Materials
3.2 Soldering Auxiliary Tools
When soldering, you can click on the tools in the top menu bar of the JLCPCB EDA PCB page and select soldering auxiliary tools. This will take you to an interactive BOM page, which displays the coordinate positions of the components on the PCB board in real time. You can check to hide or show soldered components for high-efficiency soldering.