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Introduction of Printed Circuit Board
Printed circuit board is called PCB in short form. Other name of this device is printed wiring board. Printed circuit board is used to connect different electrical components in a well fashioned way.
See the image of Printed Circuit as shown below.
It takes the form of a laminated sandwich structure consisting of conductive and insulating layers.
Each conductive layer consists of traces, planes and other features etched from one or more laminated copper layers. These types of boards are designed with artistic patterns.
Electrical components are attached, usually by soldering, to conductive pads on the outer layer of the die designed to accept the terminals of the component, providing both electrical connections and mechanical mounting. Plated holes are created to allow connection between layers.
Printed circuit boards are used in most electronic products. Alternatives to printed circuit boards include windings and point-to-point construction, which were once common but are rarely used today. Printed circuit boards require additional design work to design the circuit, but manufacturing and assembly can be automated. Electronic design automation software can be used to perform many layout jobs. Mass production of circuits using printed circuit boards is cheaper and faster than other wiring methods because the parts are assembled and wired in one operation.
A large number of cards can be created at once, and the layout can only be done once. Printed circuit boards can also be produced by hand in small batches, but are less practical. Printed circuit boards can be single-sided, double-sided or multi-layer. Multi-layer PCBs allow for much higher component densities, as traces on the inner layers take up space between components. The growing popularity of laminated printed circuit boards with more than two copper layers, especially four or more, coincides with the advent of surface mount technology. However, multilayer PCBs make it much more difficult to repair, analyze and modify circuits in the field and is generally impractical.
Types of Printed Circuit Board
- One Sided Printed Circuit Boards
- Two Sided Printed Circuit Boards
- Multilayer Printed Circuit Boards
- Rigid Printed Circuit Boards
- Flexible Printed Circuit Boards
- Rigid-Flexible Printed Circuit Boards
We will learn more about these 6 types of printed circuit boards.
1. One Sided Printed Circuit Boards
Single-sided PCB is the most common type of PCB. There is a single conductive copper layer on the board. One side of the board has the electrical components soldered or placed, and the other side shows all the etched circuitry.
Since these boards have only one layer of conductors, the conductor tracks cannot cross or overlap and occupy much space. This makes these PCBs suitable for low density design requirements. Single-sided printed circuit boards (PCBs) are used for basic, low-cost electrical equipment such as calculators, power supplies, LED lighting boards, VHF radios, and timing circuits.
2. Two Sided Printed Circuit Boards
Double-sided PCBs use a thin layer of conductive material, such as copper, to cover both the top and bottom of the board. Holes in the circuit board allow metal parts to be connected left and right. These circuit boards use one of two mounting methods, through-hole or surface mount, to connect the circuits on either side. In through-hole technology, lead components are mounted in pre-drilled holes in the circuit board and soldered to pads on the opposite side. Surface mount technology places electronic components precisely on the surface of a printed circuit board.
Double-sided PCBs are used in a variety of applications such as cellular phone systems, power monitoring, test equipment, amplifiers, HVAC applications, and UPS systems.
3. Multilayer Printed Circuit Boards
A multilayer circuit board has two or more copper layers. Circuit boards with at least three conductive layers generally fall into this category. Multilayer PCBs are constructed in a “sandwich” fashion, with multiple double-sided conductive layers separated by an equal number of layers of insulating material. All of this must be bonded and laminated under high pressure and temperature to ensure there are no air gaps and the final PCB assembly is properly stable.
Multilayer PCBs are used in computers, laptops, mobile phones, tablets, medical devices, GPS trackers, and many other complex circuits and devices.
4. Rigid Printed Circuit Boards
A rigid PCB, as the name suggests, is a PCB that cannot be twisted or bent. The base material of the panel is a rigid substrate that provides rigidity and strength to the panel. They consist of multiple layers, such as substrate layers, copper layers, solder mask layers, screen printing layers, etc., which are bonded with adhesives and heat. Some PCBs are single-sided, double-sided, or multi-layer, but rigid PCBs can be any of these depending on your needs. However, once created, it cannot be modified or changed.
Rigid PCBs are used in GPS devices, computers, laptops, tablets, cell phones, X-rays, heart monitors, CAT scans, MRI systems, temperature sensors, control tower instruments and more.
5. Flexible Printed Circuit Boards
A flexible circuit board consists of many printed circuits and components placed on a flexible substrate. Flexible circuit boards are typically made of polyamide, PEEK (polyetheretherketone), or transparent conductive polyester film. Flex circuit board, flex circuit board, flex circuit, and generic printed circuit are other names for these circuit boards.
These circuit boards are manufactured using the same components as rigid circuit boards. The main difference is that the boards are designed to bend into the desired shape during use. These PCBs are available in single-sided, double-sided, and multi-layer configurations. Contributes to reducing the complexity of unit assembly.
Flex PCBs are used in complex electronic products such as Organic Light Emitting Diode (OLED) manufacturing, LCD manufacturing, flex solar cells, automobiles, mobile phones, cameras, and laptops.
6. Rigid-Flexible Printed Circuit Boards
Rigid-flex circuit board is a hybrid circuit board that combines elements of flexible circuit board and rigid circuit board, usually formed into a curved shape or curve during the manufacturing process, which can be folded or bent continuously.
The flex portion of the board is typically used for connections between rigid boards. This allows for narrow traces that take up less space, resulting in a smaller board. Using flex circuits for connections often eliminates the need for bulky, cumbersome connectors and significantly reduces the weight of rigid-flex circuit boards. Rigid-flex PCB design is a little more complicated as these boards are built in 3D. So the board can be folded and rotated to get the desired shape for the product. Designing the board in 3D improves spatial performance and can be used in special cases where space and weight savings are required, such as Medical Devices.
Due to their compact design and light weight, rigid-flex PCBs are a great option for a variety of aerospace, medical, and consumer electronics applications.
Uses
Printed circuit boards have been used as an alternative for common applications in electronics and biomedical engineering due to the versatility of their layers, especially copper layers.
PCB layers have been used to fabricate sensors such as capacitive pressure sensors and accelerometers, actuators such as micro-valves and micro-heaters, sensor and actuator platforms for lab-on-a-chip and fuel cells are just a few examples.