12 Commonly Used Components on PCBs

21 Jan, 2022

By ren

12 Commonly Used Components on PCBs

Even though we live in a world full of electronic devices, electronics still has a mystique about it. Nothing can be seen working away to make devices operate, therefore the working mechanics of electronic projects appear to be abstract. Nothing is visible on the printed circuit board without rotating gears, shafts, and the like. You can only see the results of the current flowing, not the current itself. As a result, many would-be electronics project makers find taking up electronics making as a hobby to be a demanding task. It seems impossible to construct something without a thorough comprehension of the theory that underpins it.

In actuality, however, it is conceivable to construct projects with only a rudimentary comprehension of the theory behind them. While having a basic understanding of electronics theory would come in handy, it is not required for creating simple but practical projects. To get started, educate yourself with the components included on a circuit board and their purposes.

A Printed Circuit Board – A city that never sleeps

The components on a PCB work together to build a whole system to power our devices, similar to how cities work. When you think about it this way, the thought of having so many distinct components on a PCB doesn't seem that strange. We'll show you 15 commonly used electronic components installed on PCB to get you started!

1. Resistors

Resistors are one of the most prevalent and easiest-to-understand components on PCBs. Their purpose is to resist current flow by dispersing electric energy as heat. They come in a variety of shapes and sizes and are made of a variety of materials, but the 'axial' form resistors with leads on both long ends and colorful rings imprinted on the body are the most recognized to hobbyists. These rings are a code that shows how much resistance they have.

2. Capacitors

Capacitors are the next most frequent component on a PCB, with resistors being the only component that outnumbers them. Capacitors are used to temporarily store electric charge and then release it when additional power is required elsewhere in the circuit. It usually accomplishes this by collecting opposing charges on two conductive layers separated by an insulating, or dielectric, layer. Capacitors are frequently classified based on the conductor or dielectric material, resulting in a wide range of properties ranging from high capacitance electrolytic capacitors to varied polymer capacitors to more durable ceramic disc capacitors. Although some seem like axial resistors, the traditional capacitor is a radial design with two leads projecting from the same end.

3. Inductors

Along with resistors and capacitors, inductors are the last of the linear passive components. They store energy in the same way that capacitors do, except instead of electrostatic energy, inductors store energy in the form of a magnetic field that is generated when current passes through them. A coil of wire is the most basic inductor. The magnetic field and thus inductance increase as the number of windings increases. They can be found wrapped around a magnetic core in a variety of shapes. This significantly increases the magnetic field and, as a result, the stored energy. Inductors are frequently used to filter out or block specific signals, such as interference in radio equipment or to manipulate AC signals in conjunction with capacitors.

4. Potentiometers

Variable resistors, such as potentiometers, are a type of variable resistor. They are typically found in both rotary and linear configurations. Resistance is varied by rotating the knob of a rotary potentiometer as the slider contact moves over a semi-circular resistor. The volume controller on radios is a famous example of rotary potentiometers, as the rotary potentiometer controls the amount of current to the amplifier. The linear potentiometer is similar to the standard potentiometer, except that resistance is controlled linearly by sliding the slider contact on the resistor. When precision adjustment is necessary for the field, they are ideal.  

5. Transformers

Transformers are used to transfer power from one circuit to another by increasing or decreasing the voltage. The voltage is 'transformed,' as it were. They have a soft iron core with at least two coils of wire twisted around it, similar to inductors - the primary coil for the first, or source circuit, and the secondary coil for the circuit to which energy is transferred. Big manufacturing transformers, such as those visible on telegraph poles, scale down the voltage from overhead transmission lines, which can be several hundred thousand volts, to the few hundred volts needed for domestic use.

6. Diodes

A diode, like a one-way street, allows current to flow in only one direction, from the anode (+) to the cathode (-). (-). It accomplishes this by providing zero resistance in one direction while providing high resistance in the other. This functionality can be used to prevent current from flowing in the wrong direction, causing damage. The light-emitting diode, or LED, is the most common diode among enthusiasts. They are used to emit light, as the name implies, but everyone who has tried to solder one knows that it is a diode, therefore it is critical to get the orientation correct, or the LED will not light up.

7. Transistors

The essential building blocks of modern electronics are transistors. A single IC chip can have billions of transistors. Transistors, on the other hand, are merely amplifiers and electronic switches. They occur in a variety of shapes and sizes, with the bipolar transistor being the most prevalent. They're further divided into NPN and PNP variants. The base, collector, and emitter are the three pins of a bipolar transistor. When a current (typically a tiny current) passes from the base to the emitter in an NPN type, it activates another circuit, which causes a considerably bigger current to flow from the collector to the emitter. The directions are reversed in a PNP transistor. Field effect transistors, or FETs, are another form of transistor that is activated by an electric field.

8. Silicon-Controlled Rectifier (SCR)

SCR, also known as thyristors, are similar to transistors and diodes in that they are effectively two transistors operating together. They contain three leads as well, but instead of three, they have four silicon layers and only serve as switches, not amplifiers. Another significant distinction is that to activate the switch, only a single pulse is necessary, whereas, in the case of a single transistor, current must be delivered continually. They're better at switching to larger amounts of electricity.

9. Integrated Circuits

Integrated circuits, or ICs, are circuits and components that have been reduced down to fit onto wafers of semiconductor material. The enormous number of components that can be crammed into a single chip gave rise to the first calculators and, more recently, sophisticated computers ranging from smartphones to supercomputers. Typically, they are the brains of a larger circuit. The circuit is usually housed in a black plastic casing that can be any shape or size and has visible contacts, whether they be leads extending out from the body or contact pads right beneath the circuit, such as BGA chips.

10. Crystal Oscillators

Most circuits that require specific and steady timing elements use crystal oscillators as the clock. They generate a periodic electronic signal by causing a piezoelectric material, the crystal, to oscillate physically, hence the name. In comparison to alternative timing systems, each crystal oscillator is intended to vibrate at a set frequency and is more steady, inexpensive, and has a tiny form factor. As a result, they're frequently utilized in microcontrollers as precise timers or, more typically, quartz pocket watches.

11. Switches and Relays

The switch is a simple and easily neglected component that controls current flow in the circuit by switching between an open and closed circuit. They come in a variety of shapes and sizes, including sliders, rotary switches, pushbuttons, levers, toggle switches, key switches, and so on. A relay, on the other hand, is an electromagnetic switch that is activated by a solenoid, which acts as a temporary magnet when electricity flows through it. They can be used as switches or to magnify minor currents into larger currents.

12. Sensors

Sensors are devices that detect changes in environmental conditions and generate an electrical signal that is delivered to other electrical circuit components in response to that change. Sensors are transducers because they transform energy from a physical phenomenon into electrical energy (convert energy in one form into another). They can range from a certain type of resistor in a resistance temperature detector (RTD) to LEDs that detect infrared signals, such as those found in a television remote control. Sensors for diverse environmental stimuli, such as humidity, light, air quality, touch, sound, wetness, and motion, are available.


PCBs are made up of several distinct electrical components, each of which is critical to the device's performance. Transistors, fuses, resistors, and capacitors are examples of PCB components that all contribute to a smooth-running device; if one of these components fails, the entire PCB will fail to work, affecting the product's performance.


Write to Us And We Would Be Happy to Advise You.

    l have read and understood the privacy policy

    Do you have any questions, or would you like to speak directly with a representative?