Electric Circuit Boards
A printed circuit board (PCB) is an electrical component that contains a layer of copper on an insulating substrate. A chemical etching process divides the copper into separate conductive paths known as tracks, pads for connections and vias to pass connections between layers of copper. The track surface may have a protective coating that helps resist corrosion, shorts between traces and undesired contact with bare conductive wires. The PCB may also have a legend that provides information helpful to assembling, testing and servicing the finished product.
The type of PCB required depends on the intended function of the circuit. The power requirements, for example, will determine the active components needed to perform a specific task, such as signal amplification or rectification. Other factors include the voltage rating and current capacity of the circuit. The dielectric material used can have an impact on the signal loss tangent and the electrical properties of the circuit board, especially at high frequencies.
Typically made from thin and flexible materials, a flex electric circuit board can be bent or shaped to fit into an enclosure. These are often used in applications where space is at a premium, such as automotive or consumer electronics products. A flex circuit can also be made of rigid-flex material, a combination of rigid and flexible boards that gives the design the flexibility of a flex but the structure and mounting of a rigid circuit board.
Types of Electric Circuit Boards
Single-sided PCBs are most common and the simplest to make. They contain one layer of insulating material and are laminated with a single layer of copper, which is then etched to form the circuit traces. A single-sided PCB can be as simple as a perfboard with one conductive pad per hole or a stripboard that has parallel strips of copper instead of individual pads.
Double-sided PCBs are more complex, and they are commonly used in computers, cell phones and other consumer electronics devices. A double-sided circuit board has both sides of the insulating material laminated with a layer of copper, and the metal is connected to each other through plated through holes.
Multilayer circuit boards have three or more copper conductive layers, and they are also connected to each other through plated-through holes. A multilayer circuit board can be as simple as a two-sided PCB, but it can be as complex as a computer motherboard.
A minimal PCB designed for a single component is called a breakout board. Breakout boards place the component’s leads on separate terminals so that they can be manually connected to other components. They are particularly useful for surface-mount components with fine pitch leads. They can also be used to test the performance of a prototype circuit board. Companies making circuit boards are constantly striving to find new and improved ways to produce them more efficiently and economically. Keeping up with the demand for ever-tinier components requires investment in research and development of advanced manufacturing techniques. Moreover, people want tinier parts because they offer greater functionality and more features in smaller packages.
