This chapter is all the evolution of the Printed Circuit Board since they were invented, the changes they have undergone, through the years, their present state, and the future of these components.
A Printed Circuit Board (PCB) is a gadget that is meant to provide mechanical support and connect all the electronic components through the use of conductive pads and other features etched from copper sheets and overlaid into a material that does not conduct electricity.
Before the Printed Circuit Boards became the standard in the production of electronics, the industry majorly relied on point-to-point construction. This method led to unreliable designs and bulky products which required large sockets. The problem was eliminated when the PCB became part of the production of electronics.
The 1st Printed Circuit Boards are nearly not recognized as compared to the modern designs in the present age. The important function was for creation of an electrical path on an insulating substrate for movement and control of the electrical current. Since the invention of the first PCB, a lot of changes have been made to improve the concept. Both developments of the material and computerization have aided in the continued evolution of Printed Circuit Board into other circuits that are being used in modern days electronics.
THE FATHER OF PRINTED CIRCUIT BOARD (PCB)
Paul Eisler is the first intellectual who invented the Printed Circuit Board in the 20th century. He is, therefore, the father of the Printed Circuit Board.
He developed the PCB to operate a radio system.
Printed Circuit Boards and their year of manufacture.
- The invention of Charles Ducas in 1925 called “Printed wire” involved the creation of an electrical path direct to an insulated surface on a flat timber board. Though the concept eliminated the use of complex wiring it did not work.
- In 1936, the father of PCBs Paul Eisler developed the first PCB to be used in the radio system. The same technology was taken up by the military of the United States and was used in the proximity fuses that were used during the period of World War II.
PCB diagram of 1936.
A Proximity fuse is used to donate an explosive device automatically when the distance between the target becomes smaller than the expected value.
A fuse contains only the mechanical or electronic elements used to signal or actuate the detonator. Some fuses have a small amount of primary explosive to initiate the detonator and others may have fused with large explosive charges that include an explosive booster. The diagram below shows a proximity fuse.
A radio proximity fuse for anti-aircraft
- In 1943, Eisler continues to improve in his invention of the PCB to a higher advanced design that involved etching of the circuits on copper foil on a non-conductive material i.e., glass, paper.
The above diagram shows the 1943 Printed Circuit Board
- In 1944, Britain and the US worked together and developed proximity fuses to be used during mining, making of bombs, and artillery shells throughout of WWII.
The above diagram shows a Printed Circuit Board of 1944
- In the year 1948, the army of the US released printed circuit board tech to the citizens, and the Printed Circuit Board (Printed Wiring Boards), PWBs started to evolve.
The above diagram shows 1948 Printed Circuit Board
- In the 1950s, transistors were discovered and introduced into the market which led to a reduction in the overall size of manufactured electronics. It also made it easier to use the Printed Circuit Boards and slowly improved the eelectronic’sreliability.
A diagram showing different types of resistors
1950 Printed Circuit Board
- Between the 1950s and 1960s, double-sided Printed Circuit Boards evolved. One side consists of electrical components and the other side identification printing. The PCB designs are incorporated with zinc plates together with corrosion-resistant substances and coating are applied in order to avoid degradation.
A double-sided Printed Circuit Board
- In the 1960s, Integrated Circuit is introduced to the electronic designs industry. An (IC) also known as silicon chip-enabled millions of components to be put on that single chip producing more power and reliability than before in the electronics that had these devices. In order to accommodate a new number of Integrated Circuits, the conductors in the Printed Circuit Board had to grow higher resulting in many layers in a single PCB. The ICs are small which leads to a reduction in the size of the PCB making the connections and soldering to become difficult.
The diagram above shows the 1960 Integrated Chip/silicon chip
- During 1970, PCBs are incorrectly being connected to the dangerous polychlorinated biphenyl, PCB chemical. This resulted in confusion in the public together with the health department. The Printed Circuit board name was then changed to Printed Wiring Board (PWB) until in the 1990s when the PCBs were phased out.
The diagram below shows a 1970 PCB
- Between the 1970s and 1980s, a solder stop mask of polymer material is developed to initiate easier soldering application to the copper circuit without dividing between adjacent circuits by a greater distance increasing the circuit density. An imageable polymer material coat is developed and can be applied to circuits and modified further improvement of the circuit density.
The solder stop mask is applied to the copper traces of the Printed Circuit Board to protect it against oxidation.
Printed Circuit Board solder stop mask.
- In the 1980s, new technology was developed and was named SMT. All the previous Printed Circuit Boards had wire leads that had to be soldered into the holes of the PCB. The holes consumed a larger space which when used well could lead to the mounting of another circuit. When the surface mount technology components were introduced and were soldered directly to the small pads of the PCB without the holes. They became the manufacturing standard and were applied to replace hole components also improving power, and reliability as it leads to reducing electronic production costs.
Surface Mount Technology
DIFFERENCES BETWEEN SURFACE MOUNT TECHNOLOGY AND THROUGH-HOLE.
- Through-hole components are expensive to manufacture compared to surface mount technology.
- Surface mount technology does not have leads while through-hole components have holes for mounting.
- Surface mount technology requires advanced design compared to through-hole technology.
- Surface mount technology has a lot of mounting pins as compared to through-hole components.
- Surface mount technology enables automation at lower costs as compared to through-hole technology.
- Surface mount technology has high production at low costs as compared to through-hole technology.
ADVANTAGES OF USING SURFACE MOUNT TECHNOLOGY
- SMT designs are light due to the smaller PCB design.
- Production process setup is faster.
- SMT gives room for high circuit speeds.
- Components can be placed on two sides of the circuit board.
DISADVANTAGES OF SURFACE MOUNT TECHNOLOGY
- You require to hire a skilled person at an expensive cost.
- Tools for the components are expensive to acquire.
- Most surface mount technology components are difficult to install.
- The reliability of solder joints becomes a concern since less solder is applied to the joints.
- It is not easy to identify components.
In Through-hole technology, electronic components have leads that are inserted into drilled holes in a Printed Circuit Board and soldered to pads on the other side.
ADVANTAGES OF THROUGH-HOLE TECHNOLOGY
- It is more reliable for products that require strong connections between the layers since it can withstand a lot of stress.
- Its bonds are more expensive enabling it to be reserved for heavy components.
- It can be used with breadboard sockets.
DISADVANTAGES OF THROUGH-HOLE TECHNOLOGY
- Consumes a lot of time during production due to the drilling of multiple holes.
- Costs of production are high.
- The holes consume a lot of space on the board.
- Tracing signals is not easy.
- In the 1990s, Printed Circuit Boards continues to become smaller as CAD becomes more famous. The use of computer designs automated many steps in the Printed Circuit Board and leads to complex and advanced designs with smaller and lighter, perfect and miniature components. The manufacturers work to improve their device’s performance, reduction of electrical consumption and cost.
- In the 2000s, the Printed Circuit Boards manufactured have become tiny in size, have more layers, and are complex.
The Flexible printed circuit boards became common and provided an cost friendly option and helped in saving a lot of space which was ideal for designing packages.
An improved Printed Circuit Board of 2000
- In 2006, a process called Every Layer Interconnect (ELIC) was developed. The process uses stacked micro vias that are filled wih coper to make the connections through the layers of the PCB. This enables the developers to make proper connections between two or more layers in the board.
Since the invention of Printed Circuit Boards and their introduction of them into the market for usage, various types of PCBs have evolved as listed and discussed below.
- Single-sided/ one side printed circuit board.
- Double-sided/ two sides printed circuit board.
- Multilayer printed circuit board.
- Rigid printed circuit board.
- Flexible printed circuit board.
- Rigid-flex printed circuit board.
- High frequency printed circuit board.
- Aluminum-backed printed circuit board.
Single-sided printed circuit board
In single-sided printed circuit board, it contains only one layer of the base material. The layer which is covered with a thin layer of copper metal is a good conductor of electricity.
The PCB has a protective solder mask that is applied on top of the copper layer.
Process of making a single-sided printed circuit board
- Using any CAD designing software to make a layout of the PCB.
- Print your layout on the paper.
- Take the copper plate fiberglass PCB substrate.
- Iron the layout of the PCB on the copper side of the board.
- Place the board in a solution of copper chloride for some time for copper to etch out.
- Use a scraper to remove the laser ink from the PCB tracks
- Apply a solder mask.
- Do the drilling of holes
- Do the soldering of all the electronic components.
Benefits of a single sided-PCB in the modern market.
- The cost of production is low since fewer materials are needed.
- The probability of failing is low.
- It is easy to understand due to a smaller number of components.
- Most suitable simple designs.
Most single-sided PCBs are used in;
- Light-emitting diode.
- The relays.
- Power supply.
Double-sided printed circuit board.
A double-sided printed circuit board has two-sided traces on both the top and bottom layers. On both sides of the board, conductive copper can be mounted to allow traces of copper to cross over each other.
Advantages of double-sided PCB
- they permit density in components thus making the laying of tracks a neater process.
- It provides increased cooling.
The double-sided circuit board is applied in wide applications to satisfy the necessities of the project. The list below is where they’re applied.
- Relay controls.
- Power converters
- Controls within the industry
- Power supplies.
- Ultra-power saves systems.
- Personal control hard drives.
- Phone systems.
- Power amplifiers.
Multilayer electric circuit board
A multilayer electric circuit board is formed with three conductive layers of copper foil. Several layers of the double-sided PCBs are laminated and sticked together with layers of insulations between them..
The whole building is arranged during this the two layers are placed on each sides of the pc circuit boards to form a connection to the sarrounding. The electrical connections are achieved by plated through holes (vias)
The multilayer circuit board came into existence due to evolving changes within the industry.
Electronics became more complicated over time and need more complex circuit boards.
The computer circuit boards are affected by noise, and crosstalk which ends within the requirement of following a particular design pattern. the design considerations make it hard/difficult to urge a satisfactory performance from one or double-sided circuit board which ends up within the existence of a multilayer electrical circuit board.
Multilayer electrical circuit boards became more popular within the electronics market. they’re made of different sizes and thicknesses so that it can accommodate or fit the needs of their use. Most PCBs have an honest number of layers since an odd number of layers can cause warping within the circuit which is cost-effective to produce.
Benefits of the multilayered circuit board
- Are small in size but more powerful.
- Are light in weight since the PCB is small in size.
- Have the main quality compared to single and double-sided layer electrical circuit boards.
- Have increased durability. they’re going to bind the heat and pressure used to bind them together.
- Have flexible construction techniques.
- Are more powerful.
DISADVANTAGES OF MULTILAYER PRINTED CIRCUITS.
- they’re expensive to shop for.
- they’re difficult to style.
- Consume plenty of it slow during the manufacturing process hence tiresome.
- Their availability is proscribed within the manufacturing industry.
Multilayer circuit board is extremely applied in complex systems named below.
Electronics i.e., smartphones. Each electronic contains a PCB.
In telecommunication systems for signal transmission and satellite applications.
Industrial control systems run the machinery due to its durability and functionality.
for treatment and diagnosis.
In automotive, cars have more electronic components used for various applications within the system.
RIGID electrical circuit BOARD
because the name suggests a rigid electric circuit board cannot bend from its original shape. it isn’t flexible and thus cannot be modified or folded into the opposite desired shape.
The following are the benefits of an electric circuit board.
- Are cheaper
- it’s more durable compared to flexible circuit boards.
- Can exist for an extended period.
- Has top of the range
- Is applied to many electronic devices.
- Has more demand and supply.
Uses of the rigid circuit board
Many companies on the planet use these types of boards in several electronic gadgets because they supply increased circuit density and reduce the load of the board.
- ICT department
- Telecommunication devices.
- Signal transmission
- In satellites
- within the medical industry
- In military equipment.
FLEXIBLE electrical circuit BOARD.
It is a circuit that gives connection to the electrical components with the help of the conductive copper wires in order to convey mechanical support? it’s the muse of various electronic projects, with miniature, compact, and fewer unpredictable PCB designs.
A flexible PCB encompasses the conductive layer made out of tracks of copper.
Flexible PCBs types:
There exist four types of this flexible PCBs
- Single-Layer PCB
This as you will be ready to see from the name will have only 1 layer of copper that’s placed on top of the dielectric layer
- Multiple Layers
Has three or even more conductive copper layers that are separated apart by the dielectric substances.
- PCB with Rigid-Flex
This is a mixture of both the flexible and thus the rigid layers to form a board that will have the facility to combine many components with an excessive amount of flexibility.
- Flexible PCB from HDI
HDI is the abbreviation for high-density interconnect
- Antilock brakes
- Medical devices
- Battery packs
- Ultrasound probes
- Fuel pumps
- Motion systems
- Manufacturing devices
- Airbag apparatus
- Medical devices
- Universal Product Code equipment
- Semiconductor test
RIGID-FLEX computer circuit BOARD
The rigid-flex computer circuit board comprises rigid and versatile board technologies. The circuit card is created from several multiple flexible inner circuit layers. This has more benefits like stability, assembly, and signal transmission.
Rigid-Flex Circuits: Rigid-flex are made of many schematic layers that are connected by an epoxy pre-preg bonding film, almost like the multi-layer flex schematics. Component presence is higher in rigid-flex schematics.
The following are the advantages when employing a rigid-flex computer circuit board.
- It is flexible hence enabling the manufacturer to form without many considerations.
- Has a reduced packaging size hence light in weight.
- It is often designed to suit smaller areas.
- It will be utilized in highly demanding applications.
- Has reduced circuitry failure thanks to the mixture of rigid and flex circuits.
HIGH-FREQUENCY computer circuit BOARD
They transmit electromagnetic waves with minimal losses. it’s mainly utilized where transmissions of signals between objects are required.
The board features a symptom flow at high rates. The circuit boards are mainly applied in HDI technology.
The following are applications of high-frequency computer circuit boards.
- In communication systems
- Production of ammunition and firearms employed in the military industry.
- In the marine and aviation industries.
ALUMINUM-BAKED computer circuit BOARD
An aluminum computer circuit board is formed of a metal substrate that mainly contains a mix of aluminum.
The aluminum circuit boards are mainly employed in projects that need cooling and also the insulating dielectric is suitable for the availability of an appropriate exit for warmth.
They are mainly applied in;
- LED circuit boards.
- Used in power conversion systems.
- Applied within the motor.
We have discussed how the computer circuit boards were invented and also the various stages they underwent until this day. The invention has made the manufacturing industry grow as things still change. this can be a changing world where technology is happening we should always be able to embrace it.