Table of Contents

What is PCB Board | Types Of Printed circuit board| PCB Design

What is Printed Circuit board :

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.

Printed circuit boards are used in all but the simplest electronic products. They are also used in some electrical products, such as passive switch boxes.

Definition – What does Printed Circuit Board (PCB) mean?

A printed circuit board (PCB) is an electronic circuit used in devices to provide mechanical support and a pathway to its electronic components. It is made by combining different sheets of non-conductive material, such as fiberglass or plastic, that easily holds copper circuitry.

PCB is also known as printed wiring board (PWB) or etched wiring board (EWB).

Printed circuit boards (PCBs) is the foundation of electrical engineering, can be termed as the “brains” of any powered device. Designing PCBs is to electrical engineering something same as converting HTML to web development—the backbone that makes it all possible. It is because all powered device works with a PCB of some sort. From cell phones and remote controls to robotics and toys, PCBs provide electricity and connectivity between the components of a device, allowing it to function the way it was designed. Most often PCBs are associated with computers, but they are present almost in every electronics devices, such as:

• TVs
• Radios
• Digital cameras
• Cell phones etc.

PCB Manufacturing and Assembly

PCB Manufacturing and assembly are done in an extremely clean environment where the air and components can be kept free of contamination. Most electronic manufacturers have their own proprietary processes. While manufacturing PCBs, the majority of printed circuits are produced by bonding a copper layer over the substrate, sometimes on both of the sides, which creates a blank PCB. Then, the unwanted copper is removed after the temporary mask has been applied by etching. This only leaves the copper traces that were desired to remain on the PCB. Depending on if the volume of production is for Sample/Prototype quantities or production volume, there is a process of multiple electroplating, which is a complex process that adds traces or a thin copper layer of the substrate onto the base substrate.

PCB Materials:
• FR-4
• High TG FR-4
• PTFE
• Aluminum Base
• Rogers
• Specialized material per your request

Different Types of Printed Circuit Boards

PCBs have copper tracks to connect the holes where the various components are located They are specially designed for each and every circuit and build construction very easy. Though, making the PCB necessitates special tools. The different types of printed circuit boards mainly include the following

Single Sided PCBs
Double Sided PCBs
Multilayer PCBs
Rigid PCBs
Flex PCBs
Rigid-Flex PCBs

PCBs can be single-sided (one copper layer), double-sided (two copper layers on both sides of one substrate layer), or multi-layer (outer and inner layers of copper, alternating with layers of substrate). Multi-layer PCBs allow for much higher component density, because circuit traces on the inner layers would otherwise take up surface space between components. The rise in popularity of multilayer PCBs with more than two, and especially with more than four, copper planes was concurrent with the adoption of surface mount technology. However, multilayer PCBs make repair, analysis, and field modification of circuits much more difficult and usually impractical.

PCB Design :

Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. Rub-on dry transfers of common component footprints increased efficiency. Traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout. The finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards.

Modern PCBs are designed with dedicated layout software, generally in the following steps:

Schematic capture through an electronic design automation (EDA) tool.
Card dimensions and template are decided based on required circuitry and case of the PCB.
The positions of the components and heat sinks are determined.
Layer stack of the PCB is decided, with one to tens of layers depending on complexity.
Ground and power planes are decided. A power plane is the counterpart to a ground plane and behaves as an AC signal ground while providing DC power to the circuits mounted on the PCB. Signal interconnections are traced on signal planes. Signal planes can be on the outer as well as inner layers. For optimal EMI performance high frequency signals are routed in internal layers between power or ground planes.
Line impedance is determined using dielectric layer thickness, routing copper thickness and trace-width. Trace separation is also taken into account in case of differential signals.
Microstrip, stripline or dual stripline can be used to route signals.
Components are placed. Thermal considerations and geometry are taken into account. Vias and lands are marked.
Signal traces are routed. Electronic design automation tools usually create clearances and connections in power and ground planes automatically.
Gerber files are generated for manufacturing.

Advantages of PCB.

Miniaturized circuits
Fabrication of complex circuits over a small area is completely possible using PCB as smaller components also available cheaply and in bulk.
Increased life span
Due to the protection of electrical connections on board with the insulated mask coating, the life of PCBs increase significantly.
Easy manufacturing process
PCB designing and fabrication as a whole is relatively an inexpensive and simple task than making wired connections without any PCB.
High circuit complexity
Even the circuits with highest levels of complexity can be easily designed and fabricated which only increases the number of layers on the same PCB board.
Low electrical noise
Due to reduced length of connection wires, the effects of stray electrical signals due to neighbouring connections is reduced significantly.
Easy replication
Replication of a circuit design becomes significantly easy as once the design the ready, multiple boards can be manufactured with the same design.
Easy troubleshooting
Inspection, troubleshooting and repairing of faulty components or connections is very easy on PCBs.
Completely portable
PCBs can be moved from one place to other quite easily without any damage as compared to wired circuits.