Circuit boards have played an instrumental role in electronics over the years. However, the infatuation with market-ready electronic products has detracted from the fundamental element of electronics, which is the circuit board. It facilitates the transmission of electronic signals and ensures the proper functioning of the electronic product. Therefore, this article will delve into what the circuit board implies, its evolution, types, and overall significance.
What is a Circuit Board?
Circuit boards are synonymous with electronic products. You have used one if you have ever owned or operated an electronic product. But the definition proves elusive to most people. So what does it all entail? By definition, a circuit board implies a detached board that electrically connects and mechanically supports electronic components. The connections are through conductive tracks, while the support happens via the non-conductive substrate. Circuit boards, as a result, form the foundation of all electronic equipment and devices.
Currently, numerous types of circuit boards exist. It includes the breadboard, the stripboard, and the printed circuit board. However, all circuit boards can get traced to a common point of decent – the first circuit board. So what is the history surrounding electronic circuit boards?
The history of electronic circuit boards transcends more than one hundred and thirty years ago. It started from a simple electronic product and advanced gradually to the complex printed circuit boards commonly found in almost every electronic device or equipment. The first circuit board has its roots in the innovation of the world’s initial industrial machine. After that, the electronic circuit board evolved into smaller and complex multifunctional PCBs through gradual advancements. So how did the circuit board evolve?
The 1880-1900 Period
We associate the period with household electricity connections, initially beginning in the cities and then in rural areas. Electricity became the main alternative to wood, oil, or coal, necessitating major motors and electromagnetic devices or equipment inventions. While the electronic circuit board concept did not start in this era, it laid its inception. For instance, the AC to DC conversion question played out during this period. However, Nikola Tesla ended up finding an efficient electricity transport solution over long distances.
The 1890 – 1920 Period
The initial patent for printed circuit boards can get traced to this period. In 1903, Albert Hanson, a famous inventor from Germany, filed for a foil conductor atop an insulating board patent. The board had numerous layers. Albert described the entire concept of hole application in this patent. He demonstrated how to punch holes into the double layer besides having perpendicular wires to form electrical conductivity. It is also prudent to note that this progressive age ushered in WW1. The conflict solely focused on the trench war and mechanical devices. However, the printed circuit board concept had not come into play by this point, though it was evolving.
The 1920s period
The period saw the onset of the popular appliances that still apply today. It includes vacuums, refrigerators, washing machines, etc. Most of these appliances still had no circuit boards. However, in 1925, Ducas Chares developed and patented a description of incorporating conductive inks on the non-conductive or insulating material. It partly contributed to the rise of the PWB or printed wiring board. Further, it proved the first application related to the circuit board, as much as it only got utilized as a level heating coil.
The 1930 – 1945 Period
It is one of the most significant periods reported in the history of circuit boards or PCBs. The period characterized the WW2 or Second World War, where the United States entered the fray after the bombing of the Pearl Harbour in 1942. In this war, an electronic circuit board in the form of a proximity fuse came to the fore. The device got deployed for high-velocity artillery shells that needed firing with precision and over long distances on land or in the air. However, the fuse got initially invented by Britons to counter Hitler and his army.
The period also saw a UK-residing Austrian by the name of Paul Eisler file his patent. It encompassed a copper foil located on a glass-based non-conductive base. It is from this basis or concept that the modern-day printed circuit board borrows heavily from. Additionally, Eisler evolved the concept by using it to develop his first printed circuit board in 1943. The innovation paved the way for the current and future military application of printed circuit boards.
The period exhibited many enhancements to electronic appliances such as washing machines, vacuum cleaners, radios, and televisions. As much as the enhancement of these appliances included tremendous improvements to their corresponding circuit boards, it did not trickle down to consumer-level printed circuit boards. While the shortage of printed circuit boards persisted during this period (especially at the consumer level), the transistor came to the fore in 1947 at the Bell labs.
The 1947 – 1970 Period
The Period of 1947 to 1970 witnessed the realization of the printed circuit board’s potential upon the patenting of the PAEC or Processing of Assembling Electrical Circuit by the USA army. It paved the way for manufacturers to connect (electrical connectivity) between the electronic components using copper traces.
For instance, Hazeltine Corporation filed for a PTHT or plated through-hole tech patent in 1963. The patent allowed for the close spacing of electronic components like transistors on the circuit board without any risk of crossover connections. In the period, surface-mount technology or SMT also came to the fore through the efforts of IBM. The first practical application of the SMT approach of densely populating components in the circuit board encompassed deployment in Saturn rocket boosters.
The 1970s period
The period saw the onset of the initial microprocessor. It came as an IC or integrated circuit pioneered by Kilby Jack in 1958, though the first IC got deployed in electronic manufacturing in 1970. From this point onwards, printed circuit boards became compulsory for an efficient and functioning electronic product.
The 1980s period
The period marked the onset of the digital era, also characterized by the massive transformation of media consumption. Personal devices such as the VHS, CD, gaming consoles, camera, Walkman, etc., got introduced. It represented the digital age, some of the crucial processes involved in producing circuit boards, such as designing proved manual. However, aspects like manual drawing using stencils gradually got replaced with the advent of EDA and computers. Currently, EDA pcb design software programs like EAGLE have become instrumental in designing and influencing the manufacturing process of PCBs. It has revolutionized the design and manufacturing process of printed circuit boards. What’s more? It shifted how circuit board designs get saved from photographs to Gerber file format.
The 1990s period
It marked the onset of the internet dispensation. The period featured the widespread use of silicon, especially with the onset of BGAs. It has become possible to fit extra gates onto one chip before starting the embedding process of memories and SoC or systems-on-chip. The period also saw the miniaturization phase of the circuit boards and electronic products. While no new attributes get incorporated into printed circuit boards, the entire design process keeps changing and evolving, which has led to integrated circuits or IC.
Other aspects like DFT or design-for-testing also have to get incorporated in the design process, especially in the circuit board layout. Incorporating some leeway for future rework has now become essential aspect engineers have to consider.
The 2000s period
It is the most recent period also inferred to as the hybrid era. The period predominantly features the consolidation of electronic devices. It also features the aspect or needs for high-speed PCBs due to the emphasis on high-speed electronics. Applications areas have also expanded due to the emergence of robotics, wearables, photonics, etc. The physical miniaturization and increased complexity and density have become routine for modern-day circuit boards; the future promises more. The potential of deploying wave technology where signals get sent wirelessly instead of copper traces presents an unprecedented possibility. It will become possible to send signals without a physical medium.
Types of Circuit Boards
As an electronics enthusiast, understanding the various circuit board types is essential. It helps identify what works best for a specific type of application and how to go about its design and fabrication. Different types of electronic circuit boards exist and include the following.
It is a fundamental type of electronic circuit board that has widespread use in prototyping. It, therefore, proves popular among learners or people who embrace DIY activities, primarily in the field of electronics. The underlying reason for its popularity, especially in experimentation, is that it requires zero soldering. It is possible to use and reuse components when working with a breadboard electronic circuit.
Diverse breadboards possess different specifications, though the design often remains similar. A breadboard gets comprised of a perforated plastic block with metallic spring clips underneath. Such spring clips consist of silver, nickel, or bronze, especially on electronic components’ contact points. Metal strips play an integral role in connecting the pins to the breadboard as well. In most cases, the breadboard layout contains two distinctly different areas in bus strips and terminal strips.
- Terminal Strips. It entails the primary area of the electronic circuit board. The terminal strip consists of the area where the electronic component gets located during prototyping. It often gets denoted by a notch marking at the center of the strip area. Either side of the notch has tagged rows with letter markings. Additionally, the radial pattern interconnects the notch’s sides.
- Bus Strip. The area referred to as the bus strip functions as the power terminal or source for the electronic breadboard. It is responsible for introducing power into the electronic circuit. An average bus strip has two rows, one serving as the supply voltage and the ground.
Jumper wires get used to connecting the whole breadboard structure into one functional unit. The wires get deployed base on your peculiar needs or color codes. Circuit boards that do not use solder prove excellent resources for prototyping or simple circuits, though it has limitations.
- Solder-less breadboards prove limited, especially when it comes to operating at low frequencies. It results from the larger capacitance besides the high inductance of certain connections.
- An average breadboard has no capability of naturally accommodating SMT or surface-mount technology components without a 0.1-inch grid spacing. In such an instance, the printed circuit board breakout becomes vital.
- Breadboards by design cannot execute complicated circuit projects or designs.
While the limitations can sometimes prove restrictive, the benefits of a breadboard make it perfect for prototyping. What’s more? The components for a breadboard circuit come relatively cheap besides having the ability to get recycled or reused.
Stripboard Electronic Circuit Boards
Stripboards, also referred to as Veroboards in certain jurisdictions like the UK, represent another electronic circuit board alternative. It is an excellent option for prototyping besides the production of functional electronic circuit boards. Stripboards get characterized by rectangle grid holes with 0.1-inch dimensions besides the parallel copper strips on one of the stripboard sides. Stripboards, unlike breadboards, needs soldering. You, therefore, have to practice your technique to ensure the electrical components get soldered correctly. Further, the 0.1-inch holes require components with pins having similar dimensions.
Electrical components that mainly apply in stripboard circuit boards include DIP ICs, connectors, and any other component having a 0.1-inch pin. Such components get placed on one of the board’s sides while allowing lead protrusions on the opposite side. However, leads have to get soldered. The soldering orientation needs to ensure that leads get connected to copper traces or tracks located on the springboard’s other side. In instances that require the connection of wires, then wires measuring 0.1 inches should get utilized. Such wires can fit through holes and get soldered on the other end.
Stripboards have widespread use in developing small circuits besides getting adapted to possess extra holes for complicated projects. The need to have more complex circuit designs has also led to different variations of this board. It includes the Perf+ and Tripad. Tripad refers to a type of stripboard having sectionalized or broken conductive tracks. Every sectionalized track encompasses three holes. It also supports the connection of numerous components.
On the other hand, a Perf+ variation has some of its holes connected to the bus and not the strip, which gives it the name selective stripboards. While an incredible circuit board type for prototyping, stripboards also have limitations.
- Stripboard possessing vast amounts of holes can prove confusing when it comes to development or building it.
- It is also not the best alternative for executing complicated electronic circuit designs.
Wire Wrap Electronic Circuit Boards
It is a type of electronic circuit board that first came to the fore as an option for telephone lines. However, its successes led to its conversion and adaptation as an electronic circuit board design. Its existence provides engineers or designers the possibility of taking advantage of some of the benefits that wire wrap boards offer.
A wire wrap possesses a board containing mounted sockets. The components and the sockets supported by the board get connected through numerous wire layers wrapped around terminals, sockets, and components. The wrapping can either get accomplished manually (by hand) or using a machine. Consequently, it makes a wire wrap circuit a solder-less electronic circuit board.
Despite some obscurity regarding the wire wrap electronic circuit boards, they prove reliable and applicable designs for complicated applications. It becomes a reality because such a circuit board’s connection is immune to vibrations, unlike breadboard or soldered connections. Further, the absence of soldering elements implies that such circuit boards also prove immune or less prone to corrosion besides lesser electrical resistance.
Wire wrap electronic circuit boards have diverse applications though the primary areas involve supercomputers and the microwave. While beneficial, wire wrap electronic circuit boards also possess negatives. It is more expensive compared to other alternatives listed. Additionally, prototyping tasks become easier to accomplish with other electronic circuit board alternatives than electronic wire wraps.
Printed Circuit Board (PCB)
A popular electronic circuit board widely deployed in today’s electronic world entails the PCB. PCBs are accommodating in nature, have the flexibility to their design, and possess simplicity when it comes to usage. Such attributes make a PCB board popular among manufacturers, hobbyists, and engineers.
A printed circuit board contains etched copper tracks on a non-conductive board. Electronic components then get soldered to the copper tracks in line with the design schematic. The process of etching the copper traces to the PCB boards gets inferred as PCB printing. Printed circuit boards have diverse applications due to their integration in more straightforward and complex designs.
PCBs come in diverse types, which often get dictated primarily by the layer number and the material used. Some of the popular types of printed circuit boards entail the following.
Single-Sided Printed Circuit Boards
It is a PCB containing a single layer of substrate or base material with a copper coating. It, therefore, implies that all electronic or electrical components have to get soldered on this surface. Single-sided PCB boards get built for utilization in simple types of electronics. However, it also represents an excellent alternative for prototyping applications. Its relatively cost-effective or affordable prices give it renowned popularity among electronic hobbyists and students.
Double-Sided Printed Circuit Boards
A double-layered or double-sided PCB contains two layers of copper on either side of the non-conductive substrate layer. For this type of PCB, holes have to get drilled across the board to connect circuits on either side of the board. As a result, electrical or electronic components have to get mounted using surface-mount or through-hole technologies. Through-hole technology implies passing component leads through the drilled hole and soldering the ends to the board. On the other hand, surface-mount technology involves the component mounting on the board’s surface before soldering. SMT represents one of the typical double-sided printed circuit board types utilized by hobbyists and students.
It is a printed circuit board type that possesses multiple conductive layers (upwards of two copper layers). It often features similar characteristics as the double-sided PCB when it comes to component placing technique. The number of layers increases the functionality of the PCB as it incorporates more components.
Rigid Printed Circuit Board
It refers to a type of electronic circuit board manufacturing that adds fiberglass as part of its non-conductive substrate layer. Incorporating fiberglass brings the solidity and rigidity required to prevent the PCB from getting deformed or twist during application. In most instances, rigid printed circuit boards find application in devices that get subjected to constant movement.
Flex Printed Circuit Board
It is a printed circuit board type that utilizes plastic or flexible boards as its substrate base. The capability of a flex PCB to twist makes it integral in applications that need flexibility. Flex boards can come as double-sided, single-sided, or in a multi-layer format.
A rigid-flex printed circuit board integrates both flexible and rigid PCB formats into one unit. It, therefore, implies a type of printed circuit board containing both rigid circuit board pieces attached by flexible PCB aspects. The entire unit forms one functional unit in the respective application area.
It is an electronic circuit board mostly found in advanced and complex electronic devices. The highly evolved electronic circuit board comes miniaturized with millions of electronic components arranged in gated blocks on a single chip. ICs, unlike PCBs, have memory elements embedded which allow them to get programmed to function in a specific way. Application areas include microchips used extensively in computers.
Significance to Electronics
The importance of electronic circuit boards to electronics cannot get understated. It essentially drives every electronic equipment or device in different formats (breadboard, IC, PCB, etc.). Electronic circuit boards find application in the digital revolution across all sectors, including industry, military, aeronautics, consumer electronics, etc. However, regardless of your application area, RayMing PCB and Assembly can supply all your PCB needs.
Electronic circuit boards are essential aspects of all electronic devices. It plays a fundamental role in the revolutionary electronic aspects like IoT and smart wearables ravaging the world at the moment. Therefore, understanding what a circuit board means, its evolution, and the different types go a long way in ensuring you have the right type, design, and fabrication for your application.