An electronic component refers to any individual device or entity within an electronic system that influences the flow of electrons or their related fields. These components are typically industrial products and come in a standalone form. It is important to note that they should not be confused with electrical elements, which are theoretical representations of idealised electronic components and elements.
Electronic components consist of several electrical terminals or leads that are connected to other electrical components, typically through wires, to form an electronic circuit with a specific purpose, such as an amplifier, oscillator or radio receiver. Each component is represented by different electrical symbols and colours. These components can be packaged individually or as arrays of similar components or incorporated into packages such as integrated circuits, thick film devices or hybrid integrated circuits. Electronic components can be categorised into three types: electromechanic, active and passive components. Based on the strict physics definition, passive components are defined as those that cannot generate energy on their own, whereas active components, such as a battery, are considered as a source of energy.
Active components are dependent on an external energy source (typically ignoring the DC circuit) and have the capability of adding power to a circuit, although this is not a part of their definition. Examples of active components include amplifying elements such as triode vacuum tubes, transistors and tunnel diodes.
Passive components are unable to supply energy to the circuit. They can only use the power that is supplied by the AC circuit to which they are connected and cannot draw energy from any other source. Consequently, passive components are not capable of amplifying the power of a signal, although they can increase voltage or current, as demonstrated by a transformer or resonant circuit. Passive components include two-terminal elements such as capacitors, transformers, inductors and resistors. Electromechanical components can perform electrical functions, either through the movement of physical parts or by making electrical connections.
Now let’s analyse the five most used electrical components in electronic circuits.
Five Most Used Electrical Components in Electronic Circuits
Resistors
A resistor is a two-terminal passive electrical component that functions as a circuit element that provides electrical resistance. In electronics, resistors are utilised for various purposes, such as adjusting signal levels, limiting current flow, dividing voltages, terminating transmission lines, and biasing active elements. High-power resistors capable of dissipating a large amount of electrical power as heat can be employed in motor controls, power distribution systems, or as a test load for generators. Fixed resistors have a resistance that only experiences minor variations with temperature, time, or operating voltage. On the other hand, variable resistors can be adjusted to control circuit elements, such as a volume control or a lamp dimmer, or used as sensors for light, heat, force, humidity or chemical activity.
Resistors are frequently used elements in electrical networks and electronic circuits and can be found in virtually all electronic devices. They can be made of various materials and come in different forms as standalone components. Additionally, resistors can also be integrated into integrated circuits.
Capacitors
A capacitor is a two-terminal electrical component that stores energy as an electric charge. It is composed of two electrical conductors separated by a gap that can be filled with a vacuum or an insulating material called a dielectric. The capability of the capacitor to store electric charges is referred to as its capacitance.
Capacitors store energy by separating pairs of opposite charges. The most basic design of a capacitor is the parallel plate, which consists of two metal plates separated by a gap. However, capacitors come in a variety of forms, styles, sizes, shapes and materials. They are widely used as components in electrical circuits in many everyday electrical devices. A perfect capacitor does not lose energy, unlike a resistor. However, in reality, capacitors do experience some energy loss. When a voltage is applied across a capacitor’s terminals, such as when it is connected to a battery, an electric field forms across the dielectric, resulting in a positive charge on one plate and a negative charge on the other.
Transistors
A transistor is a semiconducting device that amplifies or switches electrical signals and power. It is a fundamental component of modern electronics and typically consists of a semiconducting material with three or more terminals for connection to an electronic circuit. A voltage or current applied to one set of terminals in a transistor influences the current flowing through another set of terminals. This allows the transistor to amplify a signal as the output power can be greater than the input power. Individual transistors can be purchased separately, but many are integrated into integrated circuits in compact form.
The MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), also referred to as the MOS transistor, is the most widely utilised transistor in a wide range of applications, including computers, electronics and communication devices such as smartphones. It is considered one of the most important inventions in electronics and is regarded as the cornerstone of modern electronics. The MOS transistor, also known as the Metal-oxide-semiconductor field-effect transistor, has played a pivotal role in shaping modern digital electronics since the late 20th century and has been instrumental in bringing about the digital age. The US Patent and Trademark Office recognises it as a game-changing invention that has greatly impacted the world and changed the way we live.
Diodes
A diode is an electronic component that permits the flow of electric current in only one direction. It is represented by a triangle symbol with a line across one vertex in electrical diagrams. The semiconductor diode, consisting of a crystalline semiconductor material with a p-n junction and two electrical connections, is the most widely utilised diode today. It has a unique current-voltage relationship that follows an exponential curve. Semiconductor diodes were the pioneers of semiconductor electronics.
“Diodes are electrical components that allow for the flow of electricity in a single direction, blocking it in the opposite direction. Represented by a triangle with a line across one vertex in circuit diagrams, diodes are made from semiconductor material with a p-n junction and two electrical terminals. Their exponential current-voltage characteristic makes them the ideal component for converting alternating current to direct current, which is achieved through the process of rectification. This property of diodes is commonly used in radio receivers to extract modulation from radio signals.
Diodes have a wide range of applications, including power conversion from AC to DC, demodulation in radio receivers, logic circuits and temperature sensing. A popular form of a diode is the light-emitting diode, which is utilised for lighting purposes and as a status indicator on electronic equipment.
Switches
An electrical circuit device that either facilitates or hinders the flow of current by breaking or establishing a connection between conductors is known as a switch. The most prevalent type of switch is the electromechanical device, which comprises movable electrical contacts linked to external circuits. When the contacts touch, an electrical current is able to flow, but when they are disconnected, no current can pass.
Switches can either be manually operated, such as a light switch or a button on a keyboard or function as sensing devices that identify the location of a machine component, liquid level, temperature or pressure, like in the case of a thermostat. There are numerous types of switches available, including rotary switches, toggle switches, mercury switches, reversing switches, push-button switches, circuit breakers and relays. One common use of switches is to control lighting, where multiple switches may be interconnected within a single circuit to offer convenient control of light fixtures. High-powered circuits require specialised construction for switches to prevent damaging arcing when opened.
