Understanding the PCB Components: A Complete Guide

Understanding the PCB Components

PCBs can appear complex and challenging at first glance. You may have come across it once if you’re new to electronic engineering. However, as a beginner, it’s important to grasp the function of a PCB and what you have to work with before attempting to design your own. So, here’s a rundown of the 13 most common PCB components.

What are printed circuit boards (PCBs)?

Printed circuit boards, or PCBs, are the fundamental components of every electronic design. A printed circuit board (PCB) combines many PCB components to make a unified, fully functional system that can power a variety of devices.

The PCB components interact in the same way as streets, subdivisions, districts, and buildings interact to construct entire cities. PCB consists of single-sided PCBs that can be single-sided (with only one copper layer) or multi-sided (with up to 20 layers). The more layers are added to a PCB, the more sophisticated it becomes, and the more advanced and complex it becomes. There are more PCB components when there are more layers. A couple of dozen electronic PCB components can easily fit on a sturdy PCB. Beginners, on the other hand, should start with the 13 most prevalent PCB components.

  • Resistors
  • Capacitors
  • Transformers
  • Transistors
  • Diodes
  • Batteries
  • Integrated Circuits
  • Oscillators
  • Inductors
  • Switches/Relays
  • Potentiometers
  • SCR
  • Sensors


Resistors are the building blocks of current control, which is why they’re so common on printed circuit boards. The “ease” with which objects enable electricity to pass through them is commonly defined as resistance. Consider the differences between insulators and conductors: the former has higher resistance than the latter.

The usage of resistors, on the other hand, allows users to exactly define the level of resistance of an object. They’re made to resist an electric current from flowing by turning the energy into heat, which is subsequently dissipated. Resistors can be built from a variety of materials and come in a variety of shapes and sizes. Resistors constructed of carbon film in the axial style are the most prevalent (and highly recommended for beginners). Both ends of the rod have leads on axial resistors. Their bodies are adorned with various colored rings that signify the resistance value of the resistor.


Capacitors are PCB components that are only outnumbered by resistors on every PCB board. Capacitors briefly store an electric charge, but resistors govern it. Consider them tiny batteries with even more tiny storage rooms. They can lose and regain full charge in a fraction of a second. As a result, capacitors are frequently used for “filtering,” which is a process in which a backup supply of energy takes over when the main source of power fails, preventing data loss or reset.

Capacitors on PCBs electrostatically store energy to be released later when power is required in the circuit. It operates by collecting opposing charges (positive and negative) on two conductive plates (usually metal) separated by some sort of insulating substance.

Capacitors are classified according to the conductive material used on the plates or the insulating material used to separate them. Polyester capacitors, ceramic capacitors, and radial capacitors are commonly used by novices and casual hobbyists. Some capacitors have the appearance of resistors. Some capacitors have the appearance of resistors. The most noticeable distinction is that resistors have leads on both ends. Two leads protrude from the same side of a capacitor.


Induction is the process by which general transformers transfer electricity from one source to another. PCB transformers work similarly. By increasing or reducing the voltage, they transport and convert electrical energy between circuits. They regulate the current in the same way as resistors do. The main distinction is that by “transforming” the voltage, they provide more electrical isolation than regulated resistance. A soft iron core and two or more distinct inductive circuits (called windings) make up a PCB transformer. The primary winding is for the source circuit, which is where the energy comes from, and the secondary winding is for the receiving circuit, which is where the energy goes. To avoid overloading or overworking the equipment, transformers break down huge quantities of voltage into smaller, more controllable currents.


Although resistors are essential for current management, transistors are essential for all modern electronics. In fact, they can be thought of as building blocks. Transistors amplify charges rather than storing, regulating, or controlling them on the PCB. The most popular type of transistor, the bipolar transistor, has three regions and three pins through which current flows and is amplified. NPN and PNP are the two types of bipolar transistors. Both have P-type and N-type areas and are made up of the (1) base, (2) collector, and (3) emitter.

Base: The complete device’s base/foundation.
Emitter: the point at which the charges are discharged or emitted.
Collector: Charge carriers are collected by the collector.

A P-type area is sandwiched between two N-type portions of an NPN bipolar transistor. A tiny current passes from the base to the emitter in an NPN type. This current then activates a second circuit, causing a considerably bigger current to flow from the collector to the emitter as well, thereby boosting (or amplifying) the current released.

An N-type area is sandwiched between two P-type sections of a PNP bipolar transistor. This reverses the current procedure of the NPN type. A tiny current passes from the collector to the emitter, triggering a greater current to flow from the base to the emitter. For a variety of reasons, NPN transistors are more widely utilized than PNP transistors.


Returning to our city-on-a-PCB analogy, diodes are the one-way streets on a printed circuit board. By allowing current to flow in one direction and prohibiting it from flowing in the other, these two-terminal PCB components control and redirect energy flow. The current usually flows from the positive terminal (also known as the anode) to the negative terminal (also known as the cathode) (called the cathode).

Diodes, like resistors, use electrical resistance to control energy flow. High resistance in one direction and zero resistance in the other effectively prevents electricity from flowing in the opposite direction, which could damage the equipment. Light-emitting diodes, or LEDs, are the most ubiquitous diode that many people—even non-hobbyists—are familiar with. Zener, high-speed switching diodes, and Schottky diodes are all examples of PCB diodes.


Theoretically, everyone understands what a battery is. Batteries are utilized by more and are perhaps the most extensively purchased component on this list. People utilize this small device to power a variety of items, including remote controls, flashlights, toys, chargers, and more.

A battery on a PCB stores chemical energy and turns it into usable electronic energy to power the board’s various circuits. To allow electrons to move from one electrode to the other, they use an external circuit. This results in a useful (though restricted) electric current. The process of converting chemical energy to electrical energy limits the current. This procedure could be completed in a matter of days for some batteries. Others may take months or even years to exhaust their chemical energy. This is why some batteries (such as those in remote controls or game controllers) need to be replaced every few months, while others (such as wristwatch batteries) take years to deplete. There are various types of batteries available for PCBs, but rechargeable batteries are highly recommended.

Integrated Circuits

Integrated circuits are the brains of all printed circuit boards. Circuits are the power factories, not batteries, which are the source of energy. Thousands (or even millions) of transistors, resistors, and capacitors are packed into these tiny wafers. They can, for example, amplify, oscillate, and process energy on a printed circuit board as a result of this. As the name implies, integrated circuits (or ICs) are circuits that have been minimized and integrated onto a PCB board. These silicone wafer-like PCB components are normally wrapped in a plastic casing. The more modern ones can also do computations using digital or analog technologies.

The two types of ICs are further defined by these technologies: digital and analog. The ideal option for novices is determined by the type of assignment to be completed. Computers and consumer devices frequently use digital integrated circuits. In audio and radio frequency amplification, Analog Integrated Circuits (also known as Linear) are commonly employed.


Crystal oscillators are programmable timers or clocks that produce electronic signals on printed circuit boards. They get their name from the fact that the frequency of an electronic signal or oscillation is determined by the resonance of a vibrating crystal formed of piezoelectric material.

The resonance can be created with a variety of piezoelectric materials, although quartz crystals are by far the most popular. The oscillator creates inverse piezoelectricity by using an electric field in conjunction with a voltage delivered to an electrode near the quartz crystal. After that, the electric field is eliminated, allowing the crystal to revert to its original shape. The quartz generates another electric field as a result of this, which generates a voltage at a specified frequency—the oscillation. Wristwatches, microcontrollers, and other similar devices commonly use crystal oscillators as precise timers.


Inductors, like resistors and capacitors, are linear passive PCB components found in printed circuit boards. Inductors, like capacitors, are two-terminal energy storage devices. Inductors, on the other hand, employ a magnetic field to store energy, whereas capacitors use an electrostatic field. Inductors, also known as coils, chokers, and reactors, are made up of a core wrapped in insulated wire. The magnetic field—and thus energy—is generated as the wire is wrapped around the core more times (i.e., the number of windings). The windings magnify the magnetic field and, as a result, the device’s stored energy and energy capacity.

Inductors are distinguished by a property known as inductance, which is defined as the ratio of voltage to the current rate of change. They’re frequently employed in audio equipment to filter or block specific signals, such as radio interference.


Another well-known PCB component, second only to batteries, is the switch. Switches are purchased by a large number of people, not just engineers and hobbyists, for casual, everyday functions. They aren’t just for use on circuit boards. They’re found in kitchens, rooms, and remote controls, among other places. Consider switches and relays as power buttons.

They essentially control the current flow in a circuit by opening and closing it. The circuit opens with a single flick of the switch, allowing current to flow to the lightbulb in the room. The circuit closes with another flick. The light is turned off and disconnected from the power supply. At least a dozen different types of switches exist, each with its physical design and look. Push-button switches, levers, and toggle switches are the most prevalent. Other types of switches include box-type, rocker, micro, slide, and rotary.


Potentiometers are just three-terminal variable resistors. They manage energy in the circuit in the same way that resistors do. They’re called so because they control a device’s electric potential or voltage. There are two types of common potentiometers: rotary and linear. Linear potentiometers are less well-known than rotary potentiometers. They employ a knob to adjust the device’s resistance, allowing the slider contact to travel across a semi-circular resistor to control how much energy is produced. The volume control knob on radios is the most common example of a rotary potentiometer in use.

The potentiometer controls the amount of current sent to the amplifier, hence adjusting the audio volume. Linear potentiometers are similar to semi-circular potentiometers, however, they have a straight line instead of a semi-circle. Consider the volume controls on today’s smartphones and headphones.


Silicon-Controlled Rectifier (SCR) is an acronym for Silicon-Controlled Rectifier. SCRs, also known as thyristors, are built up of four silicon layers, just like transistors and diodes (instead of the three NPN or PNP compositions found in transistors). They can be thought of as two transistors working together to regulate large amounts of voltage and power. In this way, they’re more suited to high-AC projects and operations when a standard transistor might not suffice. Rather than acting as amplifiers, the four layers—NPNP or PNPN—serve as switches.
Furthermore, instead of the constant current found in single or bipolar transistors, stated switches are activated by a single pulse.


Finally, but certainly not least, there are sensors. They’re relatively basic PCB components in that they “detect” physical input or changes in the environment and react accordingly. Changes in heat, light, and moisture, as well as pressure, noise, and motion, are all examples of inputs. The sensor’s reaction takes the shape of an electrical signal that corresponds to the type of change they’ve detected. This signal is then transferred to an additional circuit or PCB components.

These sensors, if designed to do so, produce an output in the form of human-readable displays or additional signals that are transmitted electronically for subsequent reading or processing. Physical energy is often converted to electrical energy through printed circuit board sensors. In a sense, this qualifies them as converters. Sensors are versatile and available in a variety of shapes and sizes. They can even be in the form of diodes, such as the red LED light on a television remote that indicates whether the item is turned on or off. Sensors are commonly used in practical applications such as humidity monitoring, air quality detection, motion sensors, and automated lighting.

Where can I find out more about PCB Components?

If you still need more information about your circuit boards after reading this, there are generally alternative resources accessible. If you’re working with a manufactured circuit board, look for the accompanying handbook. Even older technological instructions can often be found on the internet. To find them, use the search string “Inurl:pdf manual” and your search query. Google “Inurl:pdf manual GE IC3606SPCD1E” if you need a handbook for a GE IC3606SPCD1E board, or “Inurl:pdf manual GE DS200PCCAG1A” if you need a handbook for a GE DS200PCCAG1A board.


These 13 PCB components will be quite easy—and useful—to work with if you’re a beginner when designing your first PCB. Even if you’re a seasoned pro, it’s never a bad idea to brush up on the fundamentals. These PCB components all contribute to the functionality of a PCB in different ways.

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