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Common Circuit Board Components

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Printed circuit boards contain a lot of different components. All of the circuit board components that are used make the assembly process quite a complex one. However, each component is essential as the circuit board will not function correctly, if at all without them.

If you’re planning to make your own PCBs, having an understanding of what each component does is essential. Trying to create a PCB without the right components means the circuit board is likely to fail. However, depending on the missing components, the circuit board in question could overheat. This could be very dangerous as the device the PCB is sat in could catch fire.

If you wish to design your PCBs for us to manufacture, having knowledge about each component is vital. Here at Avanti Circuits, we can help you to get the printed circuit boards you need. We are a team of professionals who have been manufacturing printed circuit boards for almost 40 years. There’s almost nothing that we don’t know about PCBs and the components that are used to manufacture them.

But what components are found in printed circuit boards? Let’s take a look at this:

Components Found In Circuit Boards

Below, you will find an explanation of each of the components that are commonly found in circuit boards. Each of these components is designed to help the circuit board work well. However, no component can work on its own. It needs to be used alongside all of the other necessary components.

Please note, each printed circuit board is made for a specific purpose. One PCB may be used to switch a radio on, another could be used to capture sound and amplify it through a set of speakers. The components used in the circuit boards can differ in size, numbers, and on some occasions, shape. However, every component is as important as the one sitting next to it.


Resistors are typically one of the most common components used in a printed circuit board. In addition to this, learning how they work is relatively easy. A resistor controls the electrical current that passes through it. The function of a resistor is to resist the flow of the current by dissipating any electrical power as heat. In addition to this, a resistor will also control the voltage in every component that is connected to it.

If a resistor is not added to a circuit board the other components will be unable to deal with the voltage. This could result in the circuit board overloading. When a circuit board overloads it can fail to work well, if at all. If the correct safety features have been added to the device in question, the device should cut out the power.

Many different types of resistors are available. However, hobbyists are familiar with the axial-style resistor. A resistor such as this tends to have leads on both ends and the body will contain a few rings. Each of the rings shows the component’s resistance value.


Transformers work to transfer electrical energy between circuits. They also decrease or increase voltage. Working in a similar way to inductors, transformers are made of a soft iron core. The core has at least 2 layers of wire wrapped around it. The primary coil is to be used with the source circuit. The second coil is used to transfer energy to the circuit that needs the energy.

Transformers are typically found on telegraph poles. They work to transform the hundreds of thousands of volts to just a few hundred volts that households use.


A capacitor is a passive 2-terminal component. Working a lot like rechargeable batteries, capacitors store energy before transmitting it when it is needed. A capacitor works by collecting the opposite charges on both conductive layers. These layers are separated by either dielectric material or an insulating material.

Capacitors tend to be categorized according to the dielectric or conductor that is used. What this means is that there are many types of capacitors such as diverse polymer capacitors, high capacitance electrolytic capacitors, and ceramic disc capacitors. In addition to this, some capacitors may look similar to axial resistors. However, the most-common capacitor has a radial style with 2 leads that protrude from it.


A potentiometer is a type of variable resistor and is commonly found in linear and rotary types. The knob on a rotary potentiometer can be rotated and will result in varied resistance. This occurs when the slider contact is moved over a resistor that’s semi-circular.

Most radios have a rotary potentiometer and they work to control the volume on a radio. This is only the case when the rotary potentiometer has been added so it can control the amount of current that is sent to the amplifier.

A linear potentiometer works in almost the same way. However, the resistance can be varied when the slider is moved in a linear fashion. Linear potentiometers are ideal when a lot of fine tuning is required.


Transistors are absolutely essential to the assembly process. This is thanks to the transistor’s ability to function in multiple ways. Each transistor is a semiconductor device that has the ability to both conducts and insulate. In addition to this transistors also act as amplifiers and switches. Relatively small, transistors have a good life span and can operate happily at a lower voltage perfectly safely. No filament current is needed as a transistor can work perfectly well.

There are two types of transistors available, a field effect transistor (FET) and a bipolar junction transistor (BJT). FETs work to control the flow of current. A BJT uses holes and electrons as charge carriers.


A diode is a semiconductor that works as a 1-way switch, almost like a 1-way street. Diodes allow current to pass in 1 direction. However, it also restricts the flow of currents coming from the opposite direction. The ability to restrict flow means that less damage is likely to be caused to the circuit board, if at all. Hobbyists tend to use light-emitting diodes (LEDs). A diode such as this works to emit light. However, if you have ever tried to solder a diode, it’s important that it is oriented correctly. Failure to use the correct orientation will mean that the diode fails to light up.


Switches work to help control a power button. The power button is used to control the circuit’s flow of electricity. It does this by switching from an open circuit to a closed one, or vice versa. Switches tend to look quite different, depending on the device they are being used in. Some switches are push-button switches, others are toggle, rotary, slider, key, or lever switches.


An inductor is a passive 2-terminal component. This component works to store energy in a magnetic field. It does this when electricity passes through it. Inductors can be used to block alternating currents while also allowing direct currents to pass. Inductors can be paired with capacitors to make a tuned circuit.

Inductors are made up of a coil of wire. The more windings an inductor has, the greater the magnetic field. Many inductors tend to be wrapped around a core. This core is magnetic and it tends to come in different shapes. The magnetic field is greatly amplified and allows energy to be stored. Working to block out or filter out signals, inductors tend to be used in television and radio receivers.


Integrated circuits are found in modern electronic devices. They are also known as microchips or microelectronic circuits. Typically made up of a range of electronic circuit board components, integrated circuits are manufactured as a single unit. In this unit, small components are added. The connections between the components are built up using a thin layer of semiconductor material. As a result of this, a small chip is created. Chips such as these may only be a few centimeters or even a few millimeters in size.

Integrated circuits were first used in 1947 along with the invention of the transistor. Since then, integrated circuits have been used every day by billions of people all over the world.

– Basic types of integrated circuits

Analog and digital circuits can be used on a circuit board. However, they are both quite different. An analog circuit is made using only a few components. This means they tend to be the simplest type of integrated circuit. Connected to devices that are made to collect signals from or to the environment, this type of circuit is typically found in microphones and thermostats.

A digital circuit is quite different from its analog counterpart. This is because it is designed to accept voltages that have specific values. A circuit such as this has an on or off state and is typically used in a digital computer and a range of other devices.

– Microprocessor circuits

Microprocessor circuits are the most complicated type of integrated circuit. Made up of billions of transistors, each transistor is designed to perform a specific action. Microprocessors are built of logic circuits that synchronize with each other. Microprocessors tend to contain a computer’s central processing unit (CPU).

– Memory circuits

Microprocessors need to store quite a bit of data. The information that needs to be stored is sent to a few memory circuits. A memory circuit is made up of dense parallel circuits. These circuits use voltage states to store the required information. In addition to this, a memory circuit can temporarily store information such as a sequence of instructions of a program. The sequence of instructions or a program is typically required by the microprocessor.

– Digital signal processors

Any signal that needs to be captured electronically comes in an analog waveform. The signal, once captured, is converted into binary numbers that can be manipulated. A digital signal processor works to process the signals into a pattern of 0s and 1s.

When someone uses an analog-to-digital converter, for example, a digital representation of a recording is modified. This is undertaken by using a complex formula. The digital signal processor may recognize space in between spoken words. Any ambient noise can then be filtered out and converted back to an analog signal so someone can listen to the recording.

Processes such as these can help to filter out unwanted sounds that are often heard on live television. Digital signal processors are occasionally used to produce some digital effects on live TV. So, for example, the viewers may see some advertisements during a football game that are not actually there.

– Radio-frequency integrated circuits

Radio-frequency integrated circuits are found in many wireless devices and cell phones. Also known as RFICs, this type of circuit uses a frequency of somewhere between 3,000 hertz and up to 2.4 billion hertz. Many semiconductor circuits use at least 500 million hertz and allow components along with their electrical paths to work together.

– Monolithic microwave integrated circuits

Monolithic microwave integrated circuits tend to run between 1 and 100 GHz, otherwise known as microwave frequencies. Commonly found in cell phones (to amplify power), satellite communications, and radar systems, this type of radio-frequency integrated circuit is important.

Printed circuit boards contain a lot of different components. All of the circuit board components that are used make the assembly process quite a complex one. As you can see, there are many different types of electrical components available. However, the types of components that are detailed above are not the only electrical components available. There are many more available, each working in its own way to help a printed circuit board work well.

Many hobby printed circuit board makers are surprised by how many components are used in PCBs. However, the range of components around allow PCBs to work in many different ways. So much so, that it’s very likely almost everyone is just a few meters away from a printed circuit board. Without them, all electrical items will be unable to function. This includes cell phones, computers, remote controls, calculators, microphones, and microwaves.