Printed Circuit Board (PCB)

Definition:

A thin insulating board with conductive paths, components, and terminals etched on its surface, used to interconnect electronic components.

Components:

• Base Material: Typically epoxy glass (FR-4), but can also be other materials like ceramic, metal, or flex.
• Copper Layers: Conductors that form the circuit paths and connect components.
• Solder Mask: A protective layer that covers the copper but exposes pads for soldering.
• Silkscreen: A non-conductive layer that provides component identifiers and markings.
• Laminating Materials: Adhesives used to bond the different layers together.

Types:

• Single-Sided PCBs: Copper on one side only.
• Double-Sided PCBs: Copper on both sides.
• Multilayer PCBs: Multiple copper layers laminated together.
• Flexible PCBs: Flexible base material for applications that require bending.
• Rigid-Flex PCBs: Combine rigid and flexible sections.

Design Tools:

• Computer-Aided Design (CAD) software
• Schematic capture tools

Manufacturing Processes:

Etching:

• Creating circuit paths by removing copper from a sheet.
• Subtractive process (removing material) or additive process (plating copper).

Solder Mask and Silkscreen:

• Applied over the etched copper and cured by heat or UV light.

Laminating:

• Bonding the different layers together under heat and pressure.

Surface Mount Technology (SMT):

• Mounting components directly onto the PCB surface, without the use of holes.

Through-Hole Technology (THT):

• Drilling holes through the PCB and inserting components with leads.

Testing:

• Electrical testing to verify functionality and continuity.
• Visual inspection for defects and errors.

Applications:

• Electronic devices of all types (computers, phoness, appliances, industrial equipment)
• Aerospace and defense systems
• Medical devices
• Automotive systems
• Robotics

Advantages:

• Compact and reliable
• High performance and density
• Cost-effective for mass production
• Customization and complexity possible