Printed Circuit Board – Design, Diagram and Assembly

Printed Circuit Board – Design, Diagram and Assembly

Printed Circuit Boards (PCBs) are the heart of all modern electronics – from smartphones and smartwatches to industrial automation and aerospace systems. Whether you are a professional, beginner or an electronics hobbyist, understanding PCB design, diagrams, and assembly is key to building reliable electronic devices.

In this guide, you will learn:

• What is PCB design and assembly?
• Step-by-step PCB design process
• PCB schematic diagram basics
• How PCB assembly works
• Tools and software used in PCB design

What is PCB Design and Assembly?

PCB design refers to the process of planning and creating the layout of a printed circuit board (PCB) that connects electronic components using conductive pathways.

PCB assembly (PCBA) involves mounting those components onto the board using THT, SMT or Mixed Technology to create a functional circuit.

The combination of design and assembly is known as Printed Circuit Assembly (PCA), which is the finished product ready for testing and use.

How to Design a PCB – Step-by-Step Process

Here are 6 simple steps to design your own PCB:

 Check:

• PCB Design: A Comprehensive Guide
• Online Gerber File Viewer: Easy & Free Top 5

Simple PCB Schematic Diagram

A simple PCB schematic diagram shows how electronic components like resistors, capacitors, diodes, and Integrated Circuits (ICs) are connected. Here is a beginner-friendly example:

• Power Source → Resistor → LED → Ground

This simple design lights an LED using basic electronic components. You can create and visualize such diagrams using free PCB design software like:

• KiCad (Open-source, powerful)
• EasyEDA (Online-based, best for beginners)
• Fritzing (User-friendly for hobbyists)

Printed Circuit Board Diagram vs Schematic Diagram

Both diagrams are essential: the schematic helps with understanding the circuit logic, and the PCB Layout focuses on physical connectivity and real-world manufacturability.

What Are the Steps in PCB ssembly?

PCB assembly (PCBA) is the process of soldering or mounting components onto a manufactured bare PCB. Here are the basic steps involved in SMT PCB Assembly Process:

1. Stencil Creation – Apply solder paste through a laser-cut stencil.
2. Pick and Place – Automated SMT machine places components on the paste-covered board.
3. Reflow Soldering – The board is heated in an oven to melt the paste and solder SMD components.
4. Inspection – Quality checks via AOI (Automated Optical Inspection) and manual testing.
5. Final Testing – Power-on and functional testing to ensure the board works.

Practical Example: Designing a Real PCB Project

Suppose you are designing a smart thermostat. You would use PCB design software to:

• Create a sensor interface schematic
• Design the microcontroller layout
• Route power lines for display, Wi-Fi chip, and sensors
• Assemble the board via reflow soldering

This workflow applies across IoT devices, consumer electronics, and medical instrumentation.