What Is a PCB (Printed Circuit Board)?
A PCB (printed circuit board) is an insulating board that mechanically holds components and connects them with copper traces. It is the soldered, permanent and reliable version of a breadboard. It can be single- or multi-layer and includes traces, pads, vias and solder mask. It is the standard for mass production, small size and stable connections.
A PCB (Printed Circuit Board) is an insulating board that carries components on it and connects them to each other with copper traces. Unlike a breadboard, it's permanent, robust and suitable for mass production.
Copper Traces and Layers
The thin copper lines (traces) on the board's surface take the place of wires and connect the components. A PCB can be single-layer (copper on one side) or multilayer.
| Type | Copper layers | Use |
|---|---|---|
| Single layer | 1 | Simple, cheap circuits |
| Double layer | 2 | Common hobby/product boards |
| Multilayer | 4–16+ | Complex, dense devices |
THT and SMD Mounting
Components are mounted in two ways: THT (legs pass through holes, soldered from the back) and SMD (surface-mount, smaller). For package types, see the Component Package Types article.
The Manufacturing Process (In Brief)
First the components are drawn schematically with circuit symbols; then the traces are drawn with design software, the unwanted copper is etched off a copper-clad board, solder mask and printing are added, holes are drilled and the components are mounted.
Common Mistakes
- Routing a thin power trace: a trace carrying high current heats up if it's thin; the width should be chosen for the current.
- Neglecting the ground plane: a good GND plane reduces noise.
- Footprint error: if a component's footprint is wrong, the component won't fit; check before manufacturing.
Frequently Asked Questions
What is a PCB?+
How is it different from a breadboard?+
Why use a multi-layer PCB?+
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