The Engineering Projects

What is Flexible PCB? Definition, Material & Manufacturing

Hi Fellas! I hope you all are having fun. Today, we will have a detailed overview of Flexible PCB. We will also understand why we need to use Flex PCB? What are its advantages & disadvantage? What kind of material is used? and How to manufacture flexible PCB? etc. Flexible PCB is the most advanced type of PCB, thus quite expensive and is normally used in industrial electronic products.

I'll try to explain everything related to flexible PCB so that you could get a clear idea of what is this about and what makes it stand out from other PCB boards? Let's dive in and explore the properties of flexible PCB one by one:

What is Flexible PCB?

Initially, PCBs were designed using hard substrate materials and thus were only available in hard form(board/card shaped). With the research in technology, scientists felt the need for PCBs, that could be bend or fold easily, to place in difficult locations and this gave the idea of Flexible PCBs. Flexible PCBs were first introduced in 1950 for two main purposes:

1. For products to place on irregular surfaces i.e. Keypad.
2. To utilize the flexible areas of the product i.e. smart wrist-watch.

The most common example of a Flexible PCB is the ATM Keypad. These ATM Keypads are designed using flexible PCB so that they could be easily placed on any irregular surface i.e. circular. Moreover, smartwatches also use flexible PCBs, where PCBs are incorporated in the watch bands and because of this added space, more embedded functions can be installed in the watches. Now let's have a look at a proper Flexible PCB Definition:

Flexible PCB Definition

• Flexible PCB(also called Flex PCB/Flexible Printed Circuits(FPC)) is an advanced type of PCB and has the ability to bend, twist or fold into any shape.
• It's an incredible addition to the electronics industry as it occupies less space and is very lightweight.
• A rigid PCB is relatively easy to handle while processing a flexible PCB requires extra protocols(special clamping, material handling etc.), that's why Flexible PCB is normally costly as compared to other types of PCBs.
• In some electronic projects, both flexible and rigid PCBs are incorporated together to produce a unified product, such PCBs are termed as Rigid-Flex PCB.
• Flexible PCBs are normally used in wearable electronic products as they can easily stick with the body.

Flexible PCB Key Points

• Flexible PCBs are not that simple/cheap, thus not used by hobbyists or students and are normally designed by companies for their electronic products.
• Flex material must be not too flex or too rigid that it breaks the PCB when it is folded or twisted around the corners.
• Complex flexible products make use of reel-to-reel technology which involves advanced material handling techniques.

Why we need Flexible PCB?

Before Flexible PCB, electronic products were designed using Rigid PCB and in few products(i.e. wrist-watch), space for rigid PCB was almost negligible as compared to its complete size(including bands). To utilize such parts of electronic products(for adding extra technology/circuits), there was a need to bring flexibility in electronic PCB to fit in any shape or place and thus Flexible PCB came into existence.

Flexible PCBs have also made electronic products hand-carry i.e. Flexible Computer Keyboard. Simply roll and place it in your laptop bag. Flexible PCBs are also used in Oil & gas sector as they have the capability to sustain high temperatures.

So, now let's have a look at the Manufacturing Process of Flexible PCB:

Flexible PCB Manufacturing Process

The flexible PCB Manufacturing Process involves almost the same steps as that of MultiLayer PCB, although it involves more professionalism & expertise. Let's have a look at the steps of the Flexible PCB Manufacturing Process:

Step 1: Design CAD Model of Flex PCB

• Computer-Aided Design(CAD) models of Flexible PCBs are designed by professional designers.
• Circuit designing of flexible PCB involves multiple teams as there's a lot of factors to decide.
• Apart from designing the electronic circuitry, designers have to take care of mechanical structure & chemical materials as well because stretching or extra bending may harm the fle PCB.

Step 2: Finding Flex PCB Manufacturer

• It's the most important step of all, as we can't design flex PCB on our own, we have to take help from PCB manufacturing companies.
• So, the designers should take extra care in the selection of PCB manufacturers.
• Chinese PCB companies i.e. JLCPCB, PCBWay, WellPCB etc. offer cheap flexible PCB rates.

Step 3: How to manufacture Flex PCB?

Flexible PCBs are manufactured by a PCB company, which takes order from the user(normally designer) and delivers it according to the specified instructions. Here are the steps involved in the Flexible PCB manufacturing process:

1. Cutting: According to specified dimensions in flex design.
2. Drill Hole: Drilling of holes and vias(in case of multilayer).
3. Electroplating: It involves the placing of coppers tracks or paths.
4. Etching: Chemical treatment of Flex PCB.
5. Decorating: Involves few touch-ups of flex PCB i.e. bordering.
6. Coating: Lamination of Flex PCB.
7. Pressing
8. Solidification
9. Punching
10. Quality assurance

• Flex Circuit Overlay is a lamination process that is widely used to protect and encapsulate the external circuitry of the flexible printed circuit.
• Protective film thickness ranges from .0005" to .005", however, .001" and .002" are the most common thicknesses used.

Step 4: Flexible PCB Testing

• Flexible PCB Testing is performed after receiving the order from the PCB company.
• It's normally tested in the prototype project.

Advantages of Flexible PCB

Now let's have a look at the advantages of Flexible PCB:

1. Small-size

• Small-size is the main advantage of Flexible PCB and even in some cases, flexible PCBs are simply rolled and adjusted in small spaces.
• They have negligible width as a simple paper.

2. Light-Weight

• Flex PCBs are very light in weight as there's no cardboard(substrate core) present in them.
• Normally its weight is because of SMD components present in it.

3. High Durability

• If treated nicely, Flex PCBs normally have long lives as they are manufactured under precise conditions and in the presence of experts.
• It's also coated with formulated materials which increase its durability.

4. High Temperature

• It can withstand high temperatures and thus used in the oil & gas sector where rigid PCBs may melt out.
• Temperature withstand ability depends on the material used to design it.

5. Enhanced Capability

• Flexible Printed Circuits help in improving the overall performance of electronic products by increasing component density.
• Using Flexible components, we can add more circuitry to our autonomous products, thus enhancing their capabilities.

Now let's have a look at the disadvantages of Flexible PCB:

Disadvantages of Flex PCB

Although Flexible PCBs have a lot of advantages over Rigid PCB but their advantages are specific to certain sectors and thus we can't use them in normal projects. Here are few disadvantages of Flex PCB:

1. High Manufacturing Cost

• Flex PCB has high manufacturing costs, which makes it out of reach for hobbyists & engineering students.
• The Flexible PCB Manufacturing process is not that way and involves chemical materials for coating etc. thus it's a bit expensive.
• Online PCB companies from China i.e. JLCPCB, PCBWay etc. provide competitive rates.

2. Increased Manufacturing Time

• As compared to Rigid PCB, flex PCB requires more manufacturing time as it involves a lengthy process i.e. lamination, coating etc.
• It depends on the complexity & quantity of your products but normally takes a week for a simple order.

3. Highly Professional Designers Required

• Designing a Flexible PCB involves extra care, as if there's any designing error, you have to redo the manufacturing process.
• So, Flexible Printed Circuits are designed by a team of highly professional designers.
• Depending on the complexity of electronic design, it may involve multiple teams.

Now let's have a look at the applications of Flex PCB:

Applications of Flexible PCB

Although Flexible PCBs are not that common, thus used in specific applications only. A few Flex PCB applications are as follows:

1. Wearables

• Flex PCB is normally used in electronic wearable devices i.e. wristwatches, lockets, spy microphones, smart cameras etc.

2. Electronic Gadgets

• Flexible PCB is also used in electronic gadgets i.e. mobile phones, computer keyboards, CD/DVD drives etc.

3. Connectors

• Connectors, used in expensive electronic products, are normally designed using Flex PCB.
• Flex connectors avoid wiring & connection problems.

4. Printers

• Moving print-head of printers make use of flexible circuits that provide a pathway to connect signal with moving arm of the disk drive.

6. Consumer Electronics

• Many consumer electronics are incorporated with flexible circuits including calculators, cameras, personal entertainment devices and exercise monitors.

7. Solar Technology

• A flexible solar cell is another addition in the field of flexible electronics which are lightweight, can be folded or twisted into any shape, and are mainly used for power satellites.

That's all for today. I hope you have found this article useful. Keep updating us with your feedback and suggestions, they allow us to give you quality work that resonates with your expectations If you have any questions you can ask me in the comment section below. I'd love to help you according to the best of my expertise. Thanks for reading the article. Stay Tuned!

What is Multilayer PCB? Definition, Manufacturing & Applications

Hello Friends! I hope you all are well. Today, I am going to share the 15th lecture in the PCB learning series. I am going to give you a detailed overview of Multilayer PCB, we will cover what is Multilayer PCB? & why do we need to use it? We will also discuss its Construction, advantages, disadvantages, etc. We have seen single-sided PCB and double-sided PCB in our previous posts, so go through them first.

Let's first have a look at the definition of PCB:

• PCB is an abbreviation of the printed circuit board, which comes with different copper conductive paths, traces & pads, incorporated on a single board to electrically connect different electronic components.

So, let's get started with What is MultiLayer PCB?

What is Multilayer PCB?

Initially, electronic components were available in DIP packages only and PCB boards were used to be large-sized, thus having more space for the PCB wirings/connections. But with the research in nanotechnology, electronics get introduced with SMD(Service Mount Device) components. SMD components are very small-sized components and their sole purpose is to reduce the overall size of electronic kits/circuits. So, now when SMD components are used in PCBs, they are placed very close to each other, and in complex designs, there's not enough space to pass the tracing lines of connection wires. So, to overcome this issue, Multilayer PCBs are introduced, where connections/wirings are split across different PCB boards(called layers) and these layers are laminated to keep them insulated from each other and glued together. So, any PCB having 3 or more layers is termed a MultiLayer PCB .

I hope you understood the basic concept of MultiLayer PCB, now let's have a look at the proper definition of Multilayer PCB:

Multilayer PCB Definition

• A PCB is called Multilayer PCB, if it has 3 or more layers(sheets) of copper foil, insulated from each other(by lamination or coating) and joined together to form a single piece.
• A Multilayer PCB has an Inner Layer Core present at the center of all the layers and coated with a Copper layer from both sides, while layers of prepreg(woven glass cloth with epoxy resin) are used for insulation.
• In Multilayer PCB, outer layers(top & bottom) are single-sided PCBs , while the inner layers are double-sided PCBs .
• In multiplayer PCBs, few layers might be assigned with fixed tasks and are termed as planes i.e. power planes, ground planes .

• Layers in Multilayer PCB are normally connected with each other in 3 different styles, named as:
  • Through-hole Via.
  • Blind Via.
  • Buried Via.

What is PCB Via?

• In PCB terminology, Via is a copper-layered hole, used for connecting different layers of Multilayer PCB.
• There are 3 different styles of Vias available, discussed as follows:

1. Through-hole Via: This Via connects all layers of a multilayer PCB from top to bottom.
2. Blind Via: This Via connects any outer layer(top or bottom) with one or more inner layers of Multilayer PCB.
3. Buried Via: This Via connects any number of inner layers and never connects with any outer layer(top or bottom).

MultiLayer PCB Key Points

• Multilayer PCB is normally Rigid PCB because it's too difficult to design it in Flexible PCB format.
• Depending on projects' requirements, up to 100 layers can be incorporated in a single multilayer PCB.
• However, 4 to 8 layered PCBs are normally used for common electronics products, while some smartphones are equipped with 12 layered PCBs as well.
• Layers are tightly glued together in multilayer PCB, but if you look closely you can count layers on a single multilayer board.
• Multilayer PCBs are used on an industrial scale & nowadays every electronic product is equipped with multilayer PCB(could be multiple).
• If you check the electronic circuitry of any modern home appliance i.e. Smart LED, Mobile Phone, Laptops, etc. , you will find multilayered PCBs everywhere.
• If you are planning to design PCB online, you should have a look at these Top Online PCB Design Services .

Why do we need MultiLayer PCB?

Electronics have evolved rapidly in the past few decades. In the 1990s , mobile phones were used only to make calls or receive msgs but today, we have literally incorporated a complete computer in these small mobile devices and it won't be possible without using Multilayer PCBs. Multilayer PCB with SMD components brings smartness to electronic products by making them small-sized and thus handier. The modern world is trending towards miniaturization and multilayer PCB is playing the role of a backbone. Multilayer PCB design plays an important role in determining the functional and thermal performance of the complete electronic system, and as multilayer PCB is designed in PCB industries under modern PCB machines, thus it fulfills all standards and is durable as compared to simple PCB boards. Advanced electronic products use multilayer PCB because it allows a large number of components to incorporate on a single board, hence allowing the higher components density.

Multilayer PCB Manufacturing Process

Now let's have a look at How to Manufacture a Multilayer PCB from scratch. It involves the following steps:

Step 1: Designing CAD Model

• The first step involves the designing of the software model of Multilayer PCB .
• PCB Designing Tools i.e. Altium, Proteus, etc. are used for designing the PCB layout.
• As Multilayer PCB designs are complex so expert & professional designers are required.

Once the CAD designs of Multilayer PCB are ready, the next step is to find the suitable vendor/manufacturer for Multilayer PCB :

Step 2: Finding MultiLayer PCB Manufacturer

• It's the most important step as different PCB manufacturers are available online offering different prices & qualities.
• Few important things to check during the selection process are:
  1. Maximum number of Layers.
  2. Via styles.
  3. Layers thickness.
  4. Drill sizes.

Step 3: How to Manufacture PCB?

• The PCB designer's task has been completed, as Multilevel PCBs are manufactured by PCB companies i.e. JLCPCB, PCBWay, etc.
• In order to manufacture multilayer PCB, prepreg & core materials are joined together and are subjected to high temperature & pressure to remove any trapped air between the layers.
• Resin is used to cover the conductors around the corners, while adhesive material is melted under nominal temperature to stick different layers together.
• You can pick your material from a number of different combinations i.e. exotic ceramic, epoxy glass, or Teflon.
• It takes around 2 hours to cool off the material and will result in a hard and solid multilayer PCB board.

Step 4: Multilayer PCB Testing

• Once PCB Manufacturing company completes the product, it will ship the PCB order to the mailing address.
• Now the designer needs to unpack it and plug it in the testing workbench.
• Flexible connectors are normally used to interface Multilayer PCBs with other devices or PCBs.

Advantages of Multilayer PCB

The demand for Multilayer PCB is growing exponentially in electronics products. Multilayer PCB has numerous benefits when it comes to electronics circuit designs. Let's have a look at few advantages of Multilayer PCB:

1. Small-Size

• The main & foremost advantage of Multilayer PCB is its small size .
• Electronics Gadgets(i.e. smartphones, LCDs, microwave ovens, etc.) are updating their models and becoming slim & compact by increasing the layers of their PCBs.
• Old mobile phones(20th century) normally used 4 to 8 layered PCBs while modern mobiles are using up to 12 layered PCBs.

2. Light-Weight

• As Multilayer PCBs are small-sized and SMD components are placed on them, so they normally have very low weight .
• Because of this lightweight feature, multilayer PCBs are used in hand-held electronics devices i.e. medical devices(Heat Beat Monitors, Blood Pressure Monitors, etc.), mobile phones, electronic watches, etc.

3. High Durability

• As Multilayers PCBs are designed on a professional level, thus Multilayer PCB manufacturing process is highly advanced & precise .
• As we discussed in the Multilayer PCB manufacturing process, these PCBs are designed under professional care with formulated ingredients, that's why multilayer PCBs are highly reliable and durable.

4. More Power in Small Package

• Because of multilayer PCB, electronics circuits get reduced in size, thus giving the opportunity to add more electronic components in the same space.
• The density of components(in the same space) can also be increased by increasing the layers of PCB.
• That's the reason why our mobile devices, graphics cards, etc. are becoming slim & powerful with time.

5. Pre-Assembled

• Multilayer PCBs are designed by professional PCB companies and the Multilayer PCB manufacturing process involves machining only.
• So, the user just needs to design the PCB layout(on software) and place the order on any Multilayer PCB manufacturing company and after that, it's the job of the PCB company to provide the final product.

Disadvantages of Multilayer PCB

There are many benefits of picking multilayer PCB, but it also comes with some disadvantages/drawbacks, necessary to deal with, before making a final decision to select multilayer PCB for your next project. Here are few disadvantages of Multilayer PCB:

1. High Manufacturing Cost

• High manufacturing cost is the main disadvantage of Multilayer PCB.
• Online PCB companies from China provide competitive rates, but as the Multilayer PCB Manufacturing process is quite complex, thus it's a bit expensive.

2. Increased Manufacturing Time

• As compared to single/double layer PCB, multilayer PCB requires more manufacturing time as it involves a lengthy process i.e. printing, lamination, joining, etc.
• It depends on the complexity & quantity of your products but normally takes a week for a simple order.

3. Difficult to Debug/Repair

• As Multilayer PCBs are pre-assembled(from PCB Manufacturers) and involves SMD components, thus it's too difficult to debug or repair(if there's a fault) them as compared to simple PCBs.
• Companies normally design a prototype first to remove all errors/bugs and then go for professional design.

4. Professional Designers Required

• Designing a Multilayer PCB is not an easy task, as if there's a designing error present in the model, you have to redo the manufacturing process.
• So, PCB designing is normally carried out by a team of professional designers .
• Depending on the complexity of electronic design , it may involve multiple teams.

Applications of MultiLayer PCB

In the technology world, Multilayer PCB has become an essential requirement of electronic products. From binocular to radar systems, Multilayer PCB has found its way everywhere. Let's have a look at few applications of Multilayer PCB:

Consumer Goods

Nowadays, the human race is the slave of electronic appliances, which have become smaller, light-weight, and more functional because of Multilayer PCB. Here's a list of few consumer goods , designed using multilayer PCBs:

• Home Automation systems.
• Mobile Phones.
• Computers.
• Microwaves.
• Iron.
• Shaving Machines.

Transmission/Telecommunication Systems

Data Transmission plays a vital role in everyone's life today but most of us are not aware of what's happening behind the scene. Our mobile operator companies have big transmission plants/units where thousands of multilayer PCBs are working day & night, providing us a working mobile network. Few transmission/telecommunication systems containing multilayer PCBs are:

• Broadcasting systems.
• Radar systems.
• Mobile transmission systems.
• Signal transmission systems.
• 
  

Medical Equipment/Devices

There was a time when big ugly machines(at government hospitals) were used for blood pressure monitoring, while today we have small hand-held electronic devices to measure blood pressure. All these smart medical devices contain Multilayer PCB in them. Few examples are:

• Heart Rate Monitors
• Blood Pressure Monitors.
• ECG Devices.
• Blood Sugar Monitoring.

Few Other Examples of MultiLevel PCB

As there's a long list and we can't enlist all of them but here few other examples of Multilevel PCB :

• Atomic accelerators
• Central fire alarm systems
• Weather analysis
• Space probe equipment
• X-Ray Equipment
• GPS Technology
• File servers
• Data storage
• Cat scan technology
• Fiber optic receptors

That's all for today. I hope you have found this article useful. However, if still you feel skeptical or have any questions you can ask me in the comment section below. I'd love to help you according to the best of my expertise. We always love when you keep coming back for what we have to offer that resonates with your needs and expectations. Keep your feedback and suggestions coming, they allow us to give you quality work that helps you fill with the most relevant and useful information. Stay Tuned!

Introduction to Double-sided PCB

Hey Fellas! I hope you are enjoying your life. Today, I am going to share the 3rd chapter in the PCB learning series. In the last tutorial, we discussed Single-sided PCB in detail and today, we will have a look at the double-sided PCB. In double-sided PCB, the conductive copper layer is present on both sides of the board, unlike single-sided PCB where we have a conductive layer on a single side of the PCB. Thus, we can place electronic components on both sides of the double-sided board and normally use SMD components.

Let's jump in and explore more about double-sided PCB:

Double Sided PCB

• Double Sided PCB is a type of PCB that has conductive copper layers on both sides of the board.
• Simply put, double-sided PCB comes with two-sided traces or paths i.e. top layer and bottom layer.
• It is extremely useful in advanced electronic applications because of its small size and low cost as compared to multilayer PCB.

• Components on these boards can be connected using two different technologies i.e. Through Hole Technology and Surface Mount Technology.
  
• Double-sided PCBs are widely used in electronic industries ranging from intermediate to complex circuitry.
• They have become important in recent products because they permit closer routing traces compared to single-sided PCB.
• There are some examples where PCB comes with traces on both sides but components are connected only to one side of the board. Some people get confused if we still call it double-sided PCB if components are available only on one side of the board. But we still call it double-sided PCB even if components appear only on one side of the board because traces are present on both sides of the board.
• Soldering double-sided PCB boards is quite a tedious task, thus a pick-and-place PCB machine is normally used to solder these boards. We can't design these boards at home.
  

Construction of Double Sided PCB

• Construction of double-sided PCB is similar to single-sided PCB with some exceptions i.e. some layers are laminated on both sides of the board.
• The base of a double-sided PCB is composed of insulating material also known as a substrate which is mainly fiberglass/epoxy resin. What type of base material is used, defines if PCB board is Flexible PCB or Rigid PCB. 
• Copper foil is laminated on both sides of the substrate in case of double-sided PCB.
• Similarly, the solder mask lies above the copper foil on both sides of the board.
• There exists a silk screen above the solder mask on both sides of the board, which is mainly used for adding symbols and characters on the board so a common person can understand the board's functions.
• All these layers that are used in the construction of double-sided PCB are the same as that of single-sided PCB, but these layers are appeared on both sides of the board as compared to single-sided PCB where these layers are present only on a single side.

Advantage of Double-Sided PCB

• Double-sided PCB is an ideal choice for most professionals because of its flexibility and ease of use.
• It comes with high circuit density and pertains to lower cost as compared to multilayer complex PCBs.
• Double-sided PCB can be developed using reduced board size which ultimately helps in reducing overall cost.
  
• If you intend to sink or source current or in other words, if your board provides current to other shields or slaves, then picking a double-sided PCB makes sense. You can use the bottom layer as a ground source.
• Double-sided boards have a leg over single-sided boards in terms of their complexity because if your board is densely populated and you intend to connect a lot of components on a single board then it is better to have some components connected on the bottom side of the board.
• If you are not allowed to change board size that can limit putting thicker traces, and you are instructed to route Vcc and GND on a single board, then it is better to pick a double-sided board and route Vcc and GND on the bottom layer.

Applications

Double-sided PCBs feature a moderate level of complexity and are mostly used in a wide range of applications and deemed useful where single-layer or multiplayer PCB fails to fulfill the requirement of the project. Following are some useful applications, this is just a glimpse of applications double-sided PCBs are used for.

• Converters
• Control relays
• Power conversion
• HVAC
• LED lighting
• Instrumentation
• Industrial controls
• Power supplies
• Regulators
• UPS power system
• Traffic control system
• PC hard drives
• Vending machines
• Line reactors
• Test and monitoring equipment
• Printers
• Phone systems
• Automotive dashboards
• Power amplifiers

That's all for today. Now we have covered both single-sided and double-sided PCB. In the next lecture, we will discuss the detailed Introduction to PCB assembly. I hope you have enjoyed this article. I have tried my best to guide you with the most relevant and useful information that resonates with your needs and expectations. However, if still you feel skeptical or have any questions, you can ask me in the comment section below. I'd love to help you according to the best of my expertise. Thanks for reading the article. We feel happy when you guide us through your feedback and suggestions. They allow us to give your quality. Stay Tuned!

Introduction to Single-sided PCB

Hey Fellas! Welcome to our website. Today, I am going to share the 2nd chapter in the PCB learning series, where we will discuss Single-sided PCB in detail.

In Single-sided PCB, the copper layer is present only on one side of the PCB and the other side is used for incorporating electronic components. This type of PCB is used in simple circuits with low component density. The conductive tracks in single-sided PCB can't cross each other because of a single copper layer.

Let's dive in and explore more, I'll try to cover every aspect related to Single-sided PCB:

Single Sided PCB

• Single-sided PCB, also termed as single-layer PCB(though there's a slight difference), is the simplest type of PCB where the copper layer is present only on one side of the board while the other side is used for incorporating electronic components.
• Single-sided PCB is the simplest form of PCB and is the starting point of printed circuit board technology but still plays an important role in the electronic industry.
• These PCBs are usually cheaper to manufacture and are an ideal choice for low-density designs.
• Single-sided PCB can be designed using both Surface Mount and Though-hole technology.(We have covered in the first chapter)
• We can design single-sided PCB at home as well but it's always recommended to hire professionals for PCB designing.
  

Now, let's have a look at the difference between Single-sided PCB and Single-layer PCB:

Single-sided vs Single-layer PCB

• Single-layer PCB has only one layer of PCB but this layer could be single-sided or double-sided.
• In simple words, the single-layer PCB could have electronic components on single or both sides of the PCB
• Similarly, a multilayer PCB will have multiple single-sided and double-sided PCBs.
• So, we can say, a single-sided PCB will always be a single-layer PCB but a single-layer PCB could or couldn't be a single-sided PCB.(It may be a double-sided PCB)
  

We have studied both Single-layer and Multilayer PCB in chapter one.

History of Single-sided PCB

• Single-sided PCBs came into play in the 1950s, manufactured in the USA.
• It was produced to give components mechanical strength and a strong base with different pads and lines incorporated on it.
  
• In 1956, single-sided PCB took a big turn in terms of progress, when a number of PCB professionals from Japan took part in its manufacturing.
• Paper phenolic aldehyde was widely used in the early stage of the manufacturing process of single-sided PCB but soon it was replaced by glass fiber and epoxy resin because paper phenolic aldehyde exhibited bad solder thermal stability, low electric insulation, and twist issues.
• Glass fiber and epoxy resin give stability for a variety of temperature variations and it doesn't fluctuate or decompose too quickly.

Hobbyists who are highly interested in making convoluted circuit design find single-sided PCB useful as it gives them flexibility in routing and doing other things with ease like decoupling, proper ground connections and other electrical considerations. If you are an embedded geek, you should try Proteus Ares to create single-sided PCB designs.

Construction of Single-sided PCB

• The base material, also named as substrate, is composed of insulating fiber glass, which gives strength and a compact look. The nature and type of base material define whether the board will be a Flexible PCB or a Rigid PCB.
• Above the substrate, there lies a copper layer, that provides conducting path for various components on the board. The copper thickness is different for different boards depending on your needs and requirements and is defined in ounces per square foot.
• On the top of copper foil, there exists a solder mask layer. This layer is mainly used for protection and makes the copper foil insulating which helps in avoiding conduction in case direct contact happens with some conducting material.
• On top of all these layers, there exists a silkscreen layer that is mainly used for adding symbols and characters on the board so a common person can anticipate a clear understanding of the board.

Single Sided PCB or Double Sided PCB?

• Double-sided PCB has components on both sides of the board and it normally uses surface mount technology and thus SMD components. (We will cover it in the next chapter)
  
• Which PCB you pick depends on your needs and requirements. Before you pick any type of PCB for your project, you must take one thing into consideration that single-sided PCB layouts are more difficult to route as compared to double-sided PCB, but the following are a few conditions where you should pick single-sided PCB.
1. If you are a hobbyist or student and want to manufacture PCB at home, you must know, developing single-sided PCBs at home are much more straightforward than developing double-sided PCB.
2. Single-sided PCB is low cost. So, if you are interested in keeping your costs down, you should go for it.
   
3. Almost all HVAC systems make use of single-sided PCBs, because they are more reliable and cost-effective and don't compromise the overall quality of the product.

Advantages of Single-Sided PCB

• It is an ideal choice for designing low-density designs.
• Highly economical in nature, makes it useful for simple electronic applications i.e. car locks, kitchen hand-held appliances etc.
• As all components are present on one side of the board, the Single-sided PCB is quite easy to debug, so if you are designing a prototype to analyze your electronic circuit, you should go for a single-sided PCB.
• It undergoes a simple manufacturing process and encounters minimal manufacturing issues, making it an ideal pick for beginners.

Applications

Single-sided PCBs are widely used in many electronic applications ranging from simple to intermediate circuits. Following are some applications they can be used for.

• Vending machines
• Camera systems
• Surveillance
• Calculators
• Printers
• Solid-state drives
• Coffee makers
• LED lighting
• Packaging equipment
• Sensor products
• Power supplies
• Relays
• Radio and stereo equipment
• Timing circuits

That's all for today. In the next tutorial, we will have a look at the double-sided PCB in detail. I hope you have enjoyed the article. However, if still you feel skeptical or have any questions, you can ask me in the comment section below. I'd love to help you according to the best of my expertise. Keep your feedback and suggestions coming, they will allow us to give you quality work that resonates with your needs and expectations. Stay Tuned

Different Types of PCB(Printed Circuit Board)

Hello Everyone! I hope you all are doing well. Today, I am going to share the 12th chapter in the PCB learning series. In today's lecture, we will have a look at the Different Types of PCB(Printed Circuit Board).

We are familiar with the PCB, it is a printed circuit board that contains traces, lines and paths to electrically connect electronic components. It consists of a substrate on which copper conducting material is laminated for creating an electrical connection between components.

Let's dive in and explore these types of PCB boards:

Types of PCB(Printed Circuit Boards)

Following is the list of available types of PCB types. You can choose any PCB based on your requirements:

1. Single-Layer PCB
2. Double Layer PCB
3. Multilayer PCB
4. Rigid PCB
5. Flex PCB
6. Rigid-Flex PCB
7. High-Frequency PCB
8. Aluminium Backed PCB

1. Single Layer PCB

• A single Layer PCB contains only one layer of conductive copper foil.
• One side of the base material(substrate) is laminated with metal(normally copper) that is used to build an electrical connection between the components soldered on the board.
• Copper is mostly used for creating a conducting path because it acts as a good conductor and comes with low resistance.
• A solder mask is used on top of the copper layer which provides solid protection.
• On the top of the solder mask, there exists a silkscreen coating that is used for marking the elements on the board.
• Single-layer PCB is an ideal choice for beginners, as mostly used in simple electronics which don't involve complex circuitry.
• They are easy to manufacture and less time-consuming.
• Cheap cost and easy availability make these PCBs an ideal choice for hobbyists.
• These low-cost boards are widely used in many applications including stereo components, calculators, cameras, power supplies and printers.

2. Double-Layer PCB

• Double-Layer PCB contains two layers of copper material and substrate material is present in between these copper layers.
• Both layers are connected to each other using holes(called vias) drilled into the boards.
• Components on these PCB boards are connected using two technologies i.e. Through Hole Technology and Surface Mount Technology.
• Double-sided PCB features a moderate level of complexity and is mostly used in applications including automotive dashboards, LED lighting, vending machines, amplifiers, HVAC system, instrumentation etc.

3. Multilayer PCB

• Multilayer PCB contains multiple layers of copper and is designed with a combination of single-sided and double-sided PCB boards.
• A layer of insulation(substrate material) is placed between each board in order to provide protection that prevents the components from burning in case of excessive heat.
• Multiple layers allow the professionals to design complex designs which help in accomplishing complex electrical tasks.
• The extra layers incorporated in the multilayer design are very helpful and often used for preventing electromagnetic interference emitted by the design itself.
• Multilayer PCBs are widely used in a number of applications including Satellite systems, GPS technology, Data storage, File servers and Weather analysis systems.

4. Rigid PCB

• Rigid PCB has a hard base material(substrate), normally of fiberglass/epoxy resin and provides strength to the circuits by making them rigid.
• A computer motherboard is an ideal example of a rigid PCB that is composed of rigid substrate material.
• The motherboard is a multilayer PCB that is designed to distribute electricity from the power supply and helps in creating a conducting path between different parts of the computer including CPU, RAM and GPU.

5. Flexible PCB

• Flexible PCB can flex or transform into any shape based on needs/requirements.
• Flexible PCBs are also referred to as Flex Circuit and use plastic material in contrast to rigid PCBs, which use fiberglass that provides rigidity and strength to the PCB.
• The conducting material used in these PCBs is mostly composed of polyester, polyamide or PEEK (Polyether ether ketone).
• These PCBs pertain to a high level of complexity and come with different layers ranging from single-sided, double-sided or multi-layer flex circuits.
• The flexible nature sets these PCBs apart from others as they can be folded and wrapped around the corner.
• In order to avoid environmental hazards, flexible PCBs are composed of materials that are resistant to high-temperature oils, corrosion-resistant, waterproof and shockproof.
• These flex circuits are used in a wide range of applications including Flex solar cells, LCD fabrication, Cellular telephones, automotive industries, Laptops, cameras, LEDs and many more.

6. Rigid-Flex PCB

• Rigid-Flex PCB is manufactured when a flexible PCB is combined with a rigid PCB.
• This gives both flexibility and strength to the electronic product.
• Rigid-Flex PCB is more expensive and difficult to design as compared to Rigid or Flexible PCB.
• Less space required to construct a whole circuit and minimum weight makes these PCBs an ideal choice for handheld electronic devices including pacemakers, automobiles, cell phones and digital cameras.

7. High-Frequency PCB

• High-Frequency PCB is slightly different in terms of construction and material used for traditional PCB and is capable of transmitting signals over 1GHz.
• These PCBs are often composed of materials like polyphenylene oxide, Teflon, and glass-reinforced epoxy laminate.
• Small dielectric constant makes Teflon, an expensive choice for high-frequency PCB and it also provides low water absorption and small dielectric loss.
• You must take some things into consideration before choosing high-frequency PCB for your projects like dielectric thickness, dielectric constant and power dissipation.
• The dielectric constant is the most important feature when it comes to choosing high-frequency PCBs because if the dielectric constant changes too quickly and is unable to maintain a constant state, it leads to corrupting the digital signal which affects the overall performance of the signal.
• Similarly, dielectric loss is directly proportional to the signal loss and it also affects the signal transmission quality. Smaller dielectric loss leads to smaller signal loss.
• High-Frequency PCBs, if used in a wet environment can affect the dielectric constant.
• The material selection for making these PCBs is very important, the material you pick must be resistant to heat and hazardous chemicals and provides strength and durability to the PCB surface.

8. Aluminum-Backed PCBs

• Aluminum Backed PCBs are similar to copper PCBs with some exceptions i.e. Substrate in aluminum-backed PCBs is made up of aluminum.
• These PCBs are coupled with insulating material that provides less thermal resistance, avoiding the heat from transferring to its backing.
• Aluminum is inexpensive, making almost 8.23% of the planet's weight, and leads to the most economical manufacturing process.
• PCBs made up of aluminum are easily recyclable and non-toxic in nature.
• Aluminum is very durable than its counterparts like fiberglass or ceramic and pertains to less damage during the installation and manufacturing process.
• And aluminum is an ideal choice for dissipating heat from the circuit components, allowing the heat to transfer into the atmosphere rather than transferring it to the rest of the board.
• Aluminum Backed PCBs are widely used in high-output power applications including power supplies, automotive lights, traffic lights, motor controllers etc.
• Aluminum-baked PCBs also pertain to high mechanical stability and have the capability of bearing high mechanical stress.
• In contrast to fiberglass boards, aluminum-backed PCBs provide less thermal expansion, allowing the copper foil and insulation to stay placed on the board, hence helping in increasing the overall lifespan of the board.

That's all for today. In the next tutorial, we will have a look at the Single Layer PCB in detail. I hope you have enjoyed these different types of PCB. However, if still you feel any doubt or have any questions, you can ask me in the comment section below, I'd love to help you according to the best of my expertise. Stay tuned!

Introduction to PCB(Printed Circuit Board)

Hello everyone, I hope you all are doing great. Today, I am going to start a new tutorial series on Printed Circuit Boards, abbreviated as PCB. It's going to be a quite lengthy series so I have divided it into multiple chapters. We will start from the basics and will gradually move towards complex concepts. In this series, we will cover everything related to PCB i.e. PCB Types, materials used in PCB designing, online software and tools to design PCB layouts, online PCB Fabrication Houses to manufacture PCB etc. So, stay tuned to this series, if you want to be a PCB expert.

As today's our first chapter in this series, so we will discuss the basics of PCB i.e. What is PCB? History of PCB? How its evolved from simple boards to complex designs? What makes it useful in the latest technology? etc. So, let's hop on the board and dive in the details of PCB:

Introduction to PCB

• PCB is an acronym for Printed Circuit Board used to connect the electronics components with each other using pads and tracks incorporated on a laminated copper sheet.
• In simple words, a copper layer is laminated on an insulating sheet/board(developed using epoxy) and we place electronic components on this board.
• The copper layer has:
1. Tracks: to allow the current flow from one component to another.
2. Pads: to connect/solder electronic components to these tracks.
   
• A simple PCB board with labels is shown in the below figure.

Why do we need PCB?

• If you have worked on any electronics projects, you must have the idea of Breadboard and Verboard. Both of them are used to create electronic circuits.
• Breadboard is used normally for academic purposes i.e. when you want to study the behavior of electronic circuits. We just place our components on the breadboard and get the desired output.
  
• In the case of Veroboard, we need to solder these components, in order to make our circuit work and it's normally used in custom-build projects, where you need to design the circuit once.
• But what if, you are designing a product and you want these circuits in bulk? That's where PCB comes into action.

How to design a PCB?

• In order to design a PCB, you should have a complete understanding of electronics.
• Suppose, I want to design a PCB of a DC Motor driver, first of all, I should have a complete understanding of its circuit and that's where we use Breadboard/Veroboard.
• So, before designing a PCB, you should first create a prototype to test the working of your circuit.
• Once you are satisfied with your circuit's working/output, then move towards designing its PCB.
• In the PCB designing process, the first thing we need to do is to create a software image of the PCB circuit.
• There are different software available for PCB designing i.e. Altium, KiCAD, FreeCAD etc. (We will cover these software in our upcoming chapters)
• Once your PCB design is ready, you will get its design files and will place an order at any PCB Fabrication House.
• We can also develop a PCB board from its design on our own(will cover that) but it's always recommended to place the order on some online PCB company.
• You will get local PCB manufacturing companies as well but I would suggest you to try online PCB companies i.e. JLCPCB, PCBWay, AllPCB, PCBOnline etc.

History of PCB

Before the inception of PCB, professionals used laborious methods of point-to-point wiring, in order to connect the electronic components. This method was costly and led to complicated designs.

• In 1903, Albert Hanson presented multiple-layer flat foil conductors laminated on an insulator board.
• In 1904, Thomas Edison provided chemical methods of plating conductors on linen paper.
• In 1913, the print and etch methods were developed by Arthur Berry.
• In 1925, Charles Ducas developed electroplating circuit patterns.
• In 1936, Paul Eisler(an Australian Engineer) developed a printed circuit board as a part of the radio set.
• In 1941, a multi-layer printed circuit was developed.
• In 1943, during WW II PCB technology was used at a large scale to make proximity fuses.
• In 1947, electronic circuit-making equipment(ECME) was developed to produce three radio boards per minute.
• In 1949, the auto-assembly process is developed by Danko having component leads inserted into the interconnection pattern of copper foil and dip soldered.
• In 1952, Motorola adopted plated circuit board technology on a commercial level in home radios and announced an investment of $ 1M.
• In 1960, printed circuit boards with reduced weight, size and cost were introduced and used in radios.
• In 1980, small surface-mount parts were used instead of hole components to make PCB inexpensive.
• In 1984, the Institute of Electrical and electronics engineers( IEEE) awarded Harry W. Rubinstein an award for the development of printed components and conductors on a single insulating substrate.
• In 1990, flexible and rigid PCBs were used in different devices.
• In 1995, High-Density Interconnect(HDI) PCBs were developed.
• With the passage of time demands for electronics became prevalent, and this made professionals think they should come up with an ideal solution to make the electronics cheap and incorporated in a lesser space.

Composition of PCB

Now let's have a look at the composition of the PCB board. A simple PCB board is composed of different layers that are joined together with the help of heat and adhesive, giving the board a compact shape into a single object. These PCB board layers are named:

1. Substrate Layer.
2. Copper Layer.
3. Solder Mask Layer.
4. SilkScreen Layer.
   

Let's discuss each layer one by one.

Substrate Layer

• The base material, also known as substrate, is composed of fiber glass.
• The FR4 is the most common fiber glass used today. It is like a solid core that provides rigidity and thickness to the PCB board.
• Some PCB boards are composed of phenolics and epoxies which are not as durable as FR4 but they are less expensive and come with a unique bad smell.
• Low-end consumer electronics mostly use these types of substrates.
• Phenolics come with low decomposition temperature which allows these substrates to erupt and delaminate if solder is placed on board for a long duration of time.
• The nature of the substrate material defines whether the board will be a Flexible PCB or a Rigid PCB.

Copper Layer

• Besides the substrate, there exists a thin layer of copper foil.
• Heat and adhesive are used to laminate the copper foil on the board.
• Commonly, both sides of the substrate are laminated with copper especially in double-sided PCB, except in cheap electronics where only one side of the board is laminated with copper.
• The copper thickness varies from board to board and can be defined in ounces per square foot.
• The one ounce per square foot is suitable for most of the PCB, but applications, where we require more power, come with 2 or 3 ounces per square foot.
• Each inch per square encompasses 35 micrometers of thickness.

Solder Mask Layer

• Above the copper layer foil, there lies a solder mask layer.
• This layer is applied on the copper layer to insulate the copper layer from surroundings, in order to avoid conduction, if direct contact happens with some metal or conductive material.
• The most commonly used solder mask comes in green color, however, it's available in other colors as well.
  

Silkscreen Layer

• Above the solder mask layer, there exists a silkscreen layer that allows the user to add symbols and number for better understanding of the board.
• Silkscreen labels provide the clear indication of function of each pin and component soldered in the board.
• Silkscreen mostly comes in white color but there are also other colors available including red, grey, black, yellow etc.
• Common practice is using silkscreen in single color, as combination of different colors of silkscreen makes it difficult for the user to read the board properly.

PCB Characteristics

Though we have a lot to cover in this topic, which we will in our upcoming lectures but here I just want to mention two basic characteristics of PCB, as they are directly connected to its composition.

Through Hole Technology

• In Through-hole technology, electronic components are mounted on the PCB board with leads inserted through holes. These leads are then soldered on the other side of the board and the ends are trimmed off.
• Through-hole technology is used in simple PCBs normally single-sided PCB and double-sided PCB.
  
• Earlier PCBs were designed using through-hole technology.
  

Surface Mount Technology

• Surface mount technology came into play in the 1960s and became extensively popular till 1990.
• In surface mount technology, SMD electronic components are used, which are quite small in size and instead of leads, these components have small pads, which are soldered into the PCB surface.
• Surface mount components are 10 times smaller than through-hole components, making them an ideal choice for complex and advanced applications.
• Components placement on both sides of the PCB is a common practice in Surface mount technology, providing a much larger circuit density with a relatively smaller PCB assembly.
• Surface mount devices have a leg over through-hole devices because of their low cost and simple design.

Types of PCB Boards

PCBs can be divided into different types depending on the nature and number of layers used in the boards. Let's have a quick look at a few of them. We will cover this in detail in our upcoming lectures.

Single-Sided PCB Boards

• Single-sided PCB boards came into play in 1950 and became an ideal choice for simple electronic circuits since then.
• In single-sided PCB boards, copper tracks are found on one side of the PCB board.
• Pins of electronic components are inserted from one side of the board to the other side that comes with copper tracks and lines.
• These pins are then soldered on the copper side in order to provide the conducting path to the components.
• These types of PCBs are commonly used in many electronic devices including printers, coffee machines, basic electronics circuits and calculators.
• I have posted a tutorial Interfacing of Arduino with 2 Relay Board, in that tutorial 2 Relay Board's PCB is Single Sided PCB and is shown below:

Double-Sided PCB Boards

• Double-sided PCB boards are served as a basic component for advanced technology applications.
• In these boards, copper tracks are applied on both sides of the boards.
• In order to provide a link between two points on both sides of the boards, holes are created on the boards and then laminated with the copper layer.
• The components on these boards are electrically connected using two techniques i.e. through hole or surface mount technology.
• Using through-hole technology, leads also known as wires are inserted in the hole and then each lead is connected to the right component and builds a smooth conducting path throughout the board surface.
• Wires don't behave as connectors in surface mount technology, instead, the whole board provides a wiring surface where small leads are directly connected to the board.
• Different functions can be accomplished at a much faster rate with less space using surface mount technology which helps in minimizing the cost and makes the whole project light-weight.
• Double-sided PCB boards are widely used in applications including amplifiers, vending machines, LED lighting, HVAC systems and general power supplies.
• Here's an image of Double Sided PCB Board:

Multi-layer PCB Boards

• Multilayer PCB boards are composed of a number of double-sided PCBs.
• These boards are then glued together with pieces of insulation in order to avoid excessive heat that can damage the components.
• Multi-layer PCBs come in different forms ranging from four layers to 16 layers or more.
• The thickest multi-layer PCB ever developed by professionals was 50 layers thick.
• These boards are more complex than double-layered PCBs, help in initializing faster operations than standard PCB boards and are very similar to microchip composition.
• Multi-layer boards are used in a wide range of applications including satellite systems, weather equipment, x-ray equipment, data storage, GPS technology and many more.
• I have discussed types of PCBs based on a number of layers, however, there are other types too like Aluminum PCB and High-Frequency PCB, but they are used for more robust applications where heat dissipation is required.

Applications of PCB

Now let's have a look at the real-life applications of printed circuit boards, to get an idea of their importance. We are literally surrounded by PCB boards, from mobile chargers to mobiles itself, from dentist machines to engineering cranes, every electronic machinery has a PCB board inside it. Let's discuss a few of them:

• PCBs are widely used in industrial machinery, where thick copper PCBs are installed in motor controllers, industrial load testers, high-current battery chargers, automated machinery etc.
• Advanced medical equipment uses high-density PCBs that provide a compact and smallest design possible. The small size and light weight of PCB beautifully replace the old traditional equipment and become an ideal choice for the medical field. These devices are useful for a range of applications from small components like pacemakers to large complex machines like X-Ray machines and CAT scanners.
• Aluminum-backed PCBs are widely used in LED-based lighting systems which encompass low power consumption and high level of efficiency. These PCBs are capable of transferring heat from one point to another and are considered a step ahead of standard PCBs. These PCBs are the backbone of basic lighting solutions and LED applications.
• Automotive and aerospace industries are widely surrounded by vibration environment, this is where flexible PCBs come into play.  These PCBs can withstand high vibrations and severe environments due to their flexible and compact design. They can house in tight spaces like instrument gauges and instrument panels. Being lightweight makes it an ideal choice for manufacturing parts of transportation industries.

So, that's all for today.  In the next lecture, we will have a look at the Single-sided PCB in detail. I hope you have enjoyed the basics of Printed Circuit Boards. If you still feel skeptical or have any questions regarding PCB, you can ask me in the comment section below. Keep your feedback and suggestions coming. They help us provide you a quality work that resonates with your needs and expectations. Stay tuned!