The Most Comprehensive Introduction to PCB Components

Printed circuit boards are essential in the manufacturing process of a circuit board. But how do you go about choosing the best manufacturing board components? Many standardized off-the-shelf parts that you can quickly identify, find, and then purchase. But other details will be more proprietary to your project, meaning they’ll be more challenging to find. You’ll achieve your PCB assembly process faster if you know the parts that you need.

This article is a systematic talk of what you need when it comes to printed circuit board components. Rest assured of an easy PCB assembly process with all the necessary features.

 

What is a PCB Component?

 

A printed circuit board component is an electrical part that goes into making the entire circuit board. PCBs consist of electrical elements such as diodes, capacitors, fuses, and resistors.

For a PCB to function effectively, each component must play its role. If one part fails, the PCB may fail to function as intended.

 

(PCB components)

 

PCB Components Identification

 

PCBs are ubiquitous when it comes to almost all electronic components. When designing PCBs, the ingredients that go into the entire PCB design matter a lot; as a designer, the following is what you may need to keep at the back of your mind when it comes to PCB component identification.

 

First, determine the printed circuit board or PCB.

 

The first thing you need to do is determine the PCB that will suit your project.

There are several types of PCBs. Does your project require flex, rigid, or rigid-flex PCBs? Choosing the right PCB suitable for your project would be best.

 

Identify other “nut and bolt” electronic circuit components.

 

As a designer, you’ll have to fasten your PCBs. You’ll have to choose between nuts and bolts when it comes to fastening. Bolts come in different length sizes, but nuts have a standard size.

Again, depending on where you intend to use your PCBs, you may be forced to choose between nut or bolt fasteners.

 

The battery, fuse, diode, and transistor of the circuit board

 

A shower, diodes, fuses, and transistors are essential elements on a PCB. A battery powers the entire PCB. A transistor amplifies the charge.

A diode allows current to flow in one direction while blocking the other. A fuse breaks if too much current flows in a circuit.

 

One or more processors

 

PCBs require processors. Processors play an essential role in receiving input and providing the appropriate output.

Depending on the PCB part, you may have to include more than one processor on the PCB. Modern PCBs include several processing cores that work in unison to process instructions.

 

Connectors on smaller circuit boards (especially on the motherboard)

 

PCBs need connectors. Connectors are small electronic devices that easily and quickly interrupt or disconnect a circuit path. Connectors come in various shapes, sizes, quality levels, and complexities.

The most common connector types are one-piece card edges and two-piece board-to-board. One-piece card edges are the ideal type for small circuit boards.

 

Other chips on the circuit board

 

Plenty of components go into the manufacture of printed circuit boards. These components are also known as chips.

Many chips are required besides diodes, transistors, fuses, and diodes when designing a PCB.

Other chips that go into PCB manufacture include capacitors, LEDs, copper, and potentiometers, to mention but a few.

 

RAM (Random Access Memory) connection position on the circuit board

 

RAM is a memory of a device. It is “random access” because you can access any memory cell directly, provided you know the column and row intersecting at that cell.

On the circuit board, the connection position of the RAM matters a lot. RAM must be adjacent to the CPU socket for the best operation.

(Several PCB components on an isolated white background)

 

Identifying Polarized Circuit Board Components

 

Polarized PCB components require careful installation or soldering because they have positive and negative sides. The most straightforward way to identify this polarity is to look for the markings that indicate the sides, such as + and -.

Devices like capacitors can have color-coded sides or different terminal lengths, while diodes can have the letters A and K to mark the anode and cathode sides.

A polarized capacitor with polarity markings and different terminal lengths

Identifying the Orientation of Circuit Board Components

PCB devices like integrated circuits in different packages like BGA and QFP don’t have polarities, but you must get the orientation right during installation.

Since they have multiple pins, the first one usually has an identification dot or different color, which should correspond to the first pin’s location on the chip’s mounting pad on the board.

Passive Circuit Board Components List

Passive PCB components cannot supply power to the electrical circuit they are connected to. Instead, they can only consume power in that circuit and don’t require an external source to operate. The term “passive” technically means the components don’t provide amplification or gain, and they include the ones listed below.

Resistors

A resistor is an electronic component that opposes the flow of electrical current through a circuit, which is handy when you want to adjust signal levels, split voltage, or adjust the brightness levels of LEDs.

Several color-coded resistors soldered on a circuit board

These devices come in different types, the most notable being fixed and variable resistors. The latter is ideal for adjusting current and voltage levels in real time (volume control, lamp dimming, etc.) or sensing environmental conditions like light and humidity.

Inductors

An inductor stores energy in a magnetic field or in the form of magnetic energy when electric current flows through it. It comprises an insulated wire wound around an iron or ferrite core, and this setup opposes changes in current through them due to Lenz’s law.

An inductor with copper coils wrapped around a core

Capacitors

Capacitors store electrical charge by accumulating it on two closely spaced plates separated by a dielectric, air, or vacuum. The device creates the capacitance effect, which can filter noise, stabilize voltage regulator outputs, or create circuit resonance.

Transformers

A transformer transfers alternating current energy from one circuit to another via magnetic coupling to step up or down the voltage. This operating mechanism makes the device ideal for audio amplifiers and power supplies.

A through-hole transformer for mounting to a PCB

Fuses

These devices feature a slim conductive path or wire rated for a specific voltage and current.

If the power supply exceeds these ratings, the wire becomes too hot and melts to protect the rest of the circuit from permanent damage.

Therefore, the device's function is to protect the circuit from overcurrent conditions.

Potentiometers

Potentiometers are variable resistors that feature three terminals, where the third middle terminal connects to a sliding contact or wiper that moves over the resistive element.

This mechanism creates an adjustable voltage divider, different from the two-terminal variable resistor and ideal for volume level adjustment in audio systems.

A 10kilo-ohm concentric potentiometer next to a PCB

Varistors

Varistors are voltage-dependent resistors that protect electronic components in the circuit from voltage spikes and surges.

The device is a variable resistor, but its resistance changes depending on the applied voltage. As the voltage increases, the device’s resistance reduces.

Multiple colored varistors on a green PCB

Thermistors

Thermistors are also variable resistors that primarily act as temperature sensors.

The devices consist of metallic oxides pressed into a disk and covered in epoxy, and their resistance changes depending on the ambient temperature.

Multiple thermistors for temperature sensing

They can be NTC (Negative Temperature Coefficient) or PTC (Positive Temperature Coefficient), which operate in opposite directions.

Switches

Switches regulate the flow of electric current through circuits and require manual or physical input to cut or reconnect the power supply.

Resistor Networks

Resistors are quite common in circuits, and you can arrange them into groups or networks in one package. These networks are typical in digital circuits to accurately manage current and voltage flow.

PCB Traces

PCB transmission lines or traces are the conductive paths that transmit power and electrical signals to the components mounted on the board. Most PCB manufacturers use copper to make these lines by etching the circuit pattern on a copper foil layer.

Active Circuit Board Components List

Active circuit board components supply power to the electrical circuit, resulting in amplification.

Additionally, they can control the current flow but must have an external conditional source to provide this control. The typical active PCB components include the following.

Operational Amplifiers

Operational amplifiers are DC-coupled high-gain voltage amplifiers in an integrated circuit.

The devices amplify the voltage difference between the two inputs to produce one output, which is handy when performing arithmetic operations.

The circuit diagram of an operational amplifier

Microprocessors

These devices are tiny processing units in CPUs that can handle arithmetic and logic operations on digital signals.

Microprocessors form the brains in computers, which control various functions in medical and industrial devices and personal devices.

Transistors

Transistors play either switching or amplification roles in digital circuits.

They are miniature semiconductor building blocks for most modern electronics because they can form logic gates to perform boolean algebra.

Transistors on a circuit board

Diodes

Diodes are also semiconductors, but they are two-terminal devices that allow alternating current to flow in only one direction because they have low resistance in forward bias and high resistance in negative bias connections.

Therefore, the primary application of the device is to convert AC to DC.

Integrated Circuits (ICs)

An integrated circuit is a silicon chip containing thousands of miniaturized transistors formed on a silicon wafer and interconnected to form a circuit.

The wafer circuit also contains other tiny components like resistors and capacitors etched onto the surface.

Multiple computer chips being extracted from a wafer for packaging

Voltage Regulators

Voltage regulators are electronic devices that output a constant voltage regardless of changes or fluctuations in the input voltage and load current.

Therefore, the devices are ideal for stabilizing the voltage in a circuit and are usually located in the power supply unit.

A voltage regulator module

But some voltage regulators, like the shunt type, are passive because they don’t have active components like transistors or op-amps inside.

Silicon Controlled Rectifier (SCR)

A Silicon Controlled Rectifier (SCR) is a semiconductor switch. The primary part of this device is to control large amounts of power using small signal inputs.

Optoelectronics

These active devices convert light into electrical signals or vice versa, with the most typical ones being LEDs, photoresistors, and photodiodes.

For instance, LEDs are semiconductors that emit infrared or visible light when electric current flows through the device in forward bias.

 

PCB Component Layout: you Need to Know the Electronic Circuit

 

A PCB layout means transferring a course from a breadboard to a permanent and stable physical condition in its most basic form. There are several categories, elements, and types of electronic circuits, as highlighted below.

 

Categories of Electronic Circuits

 

Active components – Active components rely on energy sources in the system. Active sources have the capability of inducing power to the circuit.

Passive components- Passive components cannot introduce energy into an electronic circuit.

They don’t rely on DC power sources like the active components, meaning they cannot amplify signals.

 

Electronic circuit elements

 

The following are elements of electronic circuits worth noting. On a PCB, the following are some of the essential electronic circuit elements that you need to know:

Electron current – Electron current is the flow of electrons. On a circuit board, electrons flow from negative to positive terminals. Conventional wind behaves as a positive current to cause the flow of current.

Power source – When it comes to a power supply, an important thing you need to choose is the ideal type of power source for your device.

You may choose between AC and DC input depending on where you intend to use your device.

Load – An electric load is more of an electrical component that consumes electric power.

It’s different from a power source, such as a generator or battery, that produces energy.

Lights and appliances are examples of loads on a PCB.

 

Types of electronic circuits

 

There are several types of electronic circuits. Some of the main ones include the following:

Direct current – In a Direct Current electronic PCB, electricity flows in only one direction.

Smaller PCBs typically rely on direct current.
Alternating current – In an Alternating Current PCB, electricity flows in both ways while switching periodically.

AC is easy to produce, not forgetting that it can cover long distances without energy loss.

Series circuit – A series circuit PCB involves linking components one after the other in a loop.

The connection between elements is through single terminals only.

A breakage in the link ultimately leads to the failure of the entire circuit.

Parallel circuit – Unlike series circuits, parallel circuits PCBs involve the placement of components in separate branches.

In parallel circuits, the link between parts is through both ends, but in different chapters.

If the relationship breaks in a parallel circuit, only the branch with damage is affected.

 

(A close pic of a high-tech PCB)

 

How to Choose the Right PCB Components

 

Circuit boards may seem somewhat incomprehensible, but their components matter a lot. The functioning of a PCB depends on its members.

So, how do you go about choosing the right PCB components? Here’s what you need to do.

 

PCB design

 

Choose suitable components – You need to select the right parts for your board for the best functioning PCBs.

Go for the best materials that will suit your board. Ensure that your diodes, anodes, and transistors are of the highest quality.

 

Use schematics to plan your project.

 

Schematics are of importance when designing a PCB. With the help of schematics, you will be able to better position.

To know where every PCB will fit and how to maintain and repair your PCB in case of damage.

 

Required space element/component size

 

What’s the size of your electronic component(s)? If it’s too large, then you may require a giant board. Still, you may need larger components on your PCB for better functionality.

 

Consider Component Footprint

 

Your PCB component footprint has to include important pieces of information. Things such as assembly, placement, and part numbers are invaluable and need to be present in a component footprint.

When creating a PCB footprint, make sure that you keep your entire datasheets handy. Also, understand the standard package sizes and watch for through-hole sizes and locations.

 

Follow acceptable grounding practices.

 

When designing a PCB, you need to stick to some grounding rules. Grounding is essential in your design process.

Without a stable ground, you may not be able to ensure the passage of clean signals from one component to another.

Some essential grounding practices involve leaving nothing unattached, grounding before routing, and minimizing series vias.

 

PCB soldering-choose right components

 

PCB soldering may seem straightforward, but you may end up with a low board if you do it wrongly. If you desire a good board, ensure you go for the right equipment.

Ensure that the soldering iron and the solder are of the highest quality. If you employ the wrong components, you may have a printed circuit board that won’t serve you properly.

 

Separate lead from lead-free components

 

Leaded solder has been a popular go-to substance in rework and electronic manufacturing for many years.

But in the last few decades, there’s been a growing concern for an environmental and increasing problem with products made using lead.

The choice between leaded or unleaded components depends on the size of your project.

However, due to the latest government directives, you may have to go for unleaded components.

Lead-free components are known for being environmentally friendly and not hazardous to humans.

 

Do you need padding?

 

A PCB pad is the exposed surface of a printed circuit board where components get mounted and soldered.

Pads have different styles and shapes, depending on the components soldered to the place.

Padding avoids flashovers and tracking that may occur between electrical conductors.

 

The pad design matches the lead setting on the component.

 

This is simple. The pad design needs to match the lead on the part. Ensure that the pads match the lead settings to avoid imbalances in the solder joints as much as possible.

 

Consider Component Packaging Options

 

You must select a component package that can add some perfection to your overall design.

With an excellent components package, you’ll improve your image as a proficient PCB designer.

A useful components package supplements your aesthetic design and attracts more customers.

 

(A correctly assembled PCB)

 

How to Solder PCB Components

 

Soldering involves using a filler material, or solder, to combine some metal pieces.

Soldering occurs at relatively low temperatures compared to welding and brazing, which require high temperatures.

 

Solder PCB components

 

You’ll need the right equipment and a clean working surface to sell PCB components. You begin the whole process by placing pieces into the holes.

You need to place the components so that the legs effectively come out on the same side as the solder pads. On the PCB solder side, make sure that you carefully bend the legs of the components a bit. By doing so, it will not fall out if you flip the board upside down.

In short, when soldering components on a printed circuit board, ensure you have the right tools.

Work on a clean surface while ensuring that you follow all the steps. Don’t forget to keep all the safety precautions to don’t injure yourself or your colleagues.

 

How to place components on PCB

 

Placing components on a PCB isn’t a difficult task. First, you have to group the elements by function.

Next, you need to keep the details away from the dissipating area. After that, make sure that you place the board-to-wire connectors near the edge.

After that, get the orientation of the components standardized before finally making space for copper traces.

 

How to remove components from PCB

 

Removing parts on a PCB is an easy three-step process. First, you need to inspect the size of the solder joints on the roll that requires removal.

Next, you must apply a small amount of liquid flux to solder joints of the features you want to remove.

Lastly, carefully place a heated soldering iron tip on the board’s component side's lead to remove the part (s).

 

(PCB soldering)

 

Can the PCB Components Age?

 

PCB components can age. However, as discussed below, there are several reasons why printed circuit components age,

When something goes wrong during the manufacturing age, PCBs can age quickly. Still, printed circuit boards can age after being used for a very long time.

 

Why do PCB components fail because of old age?

 

PCBs can fail due to old age. After functioning for a very long time without replacement, PCBs age.

Because of old age, printed circuit boards will not function properly. After some time in service, there’s a need to replace printed circuit boards or printed circuit board components.

Diodes, transistors, and transformers need replacement after long service.

The average functioning time of these is close to 10 years. After a decade of working, such components may need replacing.

 

How to prevent the aging of PCB components

 

There are several ways of controlling the aging of printed circuit board components. While it’s hard to avoid the failure caused by age, the costs of replacing parts are controllable.

As a designer, you can avoid such costs by swapping old components for new ones. To prevent PCB components’ aging, ensure you use quality materials during PCB manufacture.

Also, ensure that you correctly place your details and avoid the usage of burned components. If you use burned components, then they will age within a short time.

Much worse, if you place your details poorly, they will age quickly.

If you want to avoid rapid aging, make sure that you employ the best soldering techniques. Make sure that you avoid matters to do with chemical or fluid leakage during soldering.

 

(A picture of an aged PCB)

 

How to Order PCB Components

 

Based on the increase in the demand for electronic components, getting PCB components that meet your needs has to be easy.

Before ordering the right parts, you need to take some time to determine if they’ll meet your needs.

The components that go into your printed circuit board will decide on its overall functionality.

Before ordering PCB components, you need to look at different manufacturing options.

Depending on the size of your project, you may require either small or large quantities.

 

Channel selection

 

When you want to order your PCB components, you must ensure that you select the best supplier.

Channels selection involves the identification of the most reliable suppliers. It also involves getting to know whether prospective members are suitable.

Lastly, channel selection involves securing prospective suppliers for the channel.

 

 Correctly recognize the manufacturer’s part number (MPN)

 

A manufacturer part number identifies particular part designs used in a given industry.

The primary purpose of a manufacturer’s part number is to simplify the reference to that specific part.

A part number does identify a part design within a single or several corporations.

The easiest way to determine the manufacturer’s part number is on the product itself.

If you cannot find it on the product, you can find it on the invoice. When selecting PCB components, you must ensure they come with the manufacturer’s part number.

A manufacturer part number enables you and your manufacturer to reference and identify parts quickly.

Additionally, MPN ensures that your manufacturer can quickly process design revisions with little chance of error.

 

Quantity ordered

 

Quantity ordered refers to the overall number of stock-keeping units you request from a supplier. These units aren’t counted as part of the quantity on hand till they arrive.

Knowing the amount to order is essential as it will prevent the duplication of orders of the same items. The same is true when it comes to PCBs.

As a PCB designer, you need to know the number of components to avoid parts duplication.

 

Avoid parts mismatch

 

When ordering PCBs, there’s nothing worse than being supplied with parts that don’t match.

Component mismatch is one of the worst things when it comes to PCB assembly.

If you want to avoid parts mismatch, ensure you have a missing aperture list and a missing drill file.

Also, ensure you have a missing Gerber file and tool list. You’ll boost your chances of minimizing parts mismatch with all these files.

 

Consider the expected cost issue.

 

Ordering costs are the expenses that you’ll incur to create and process your order. When ordering printed circuit board components, you need to factor in the expected costs.

If you bump into a cheap manufacturer, their products probably aren’t of high quality. You need to ensure that the value of the product matches its quality.

 

Future Trends in Circuit Board Components

 

Higher efficiency and miniaturization are the future of technology, and the future trends in PCB components should match these factors.

So, you should expect higher frequency components with more efficient power management to enhance processing speeds while lengthening the battery life.

Discrete component integration into a single device to consolidate their functions will also be common.

 

Summary

 

Printed circuit boards are the basis of almost all electronics and technology worldwide. There are different types of circuit boards, all suitable for the project at hand.

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