An Overview of Electronic Components

Like how proteins are the building blocks of life, components are the building blocks of electronic products. A PCB is the skeletal structure that is designed to compactly accommodate these components, hold them together, and establish a robust connection to achieve the intended output.

The most widely used electronic components are resistors, capacitors, transistors, inductors, ICs, and LEDs. These components usually have leads (polarities) or are available in specific packages that the designer can choose to suit his circuit requirements. SMT (Surface Mount Technology) and through-hole are the two types of mounting techniques used to place components on a PCB.

Passive and active components are the two kinds of components utilized in electronic circuits.

Passive components

The semiconductor devices that do not require an external power source for their operation are called passive components. Here, the components don’t require any specific current or voltage to perform its operation.

Below are a few passive components for your reference:


  • The resistors control voltage and current in an electronic circuit.  
  • The voltage (V), current (I) and resistance (R) are related by Ohm’s law. i.e. V = IR.
  • Resistors are one of the best ways to control the current flow and voltage in an electronic circuit. 
  • The unit of resistance is Ohms (Ω).


  • Capacitors are electronic components that store electrical energy.
  • They perform the charging and discharging operation.
  • The capacitors are implemented to bring in time delay in a circuit.
  • They block DC signals and allow AC signals to pass through. 
  • The capacitors filter out the noise and help stabilize the supply voltage of a circuit.
  • The charge (Q), voltage (V), and capacitance (C) are related by C = Q/V.
  • The unit of capacitance is Faraday (F).

Active components

The semiconductor devices that depend on an external power source for their operation are called active components. Some of the active components are:


  • Transistors are three-terminal components. Primarily, they act as switches that are controlled by an electrical signal. They can also amplify the signals as per the design requirements.


  • Diodes are two-terminal semiconductor devices with an anode and a cathode.
  • The predominant feature of a diode is that they conduct electric current in only one direction.

Electronic Component Part number, Datasheet, and Distributors

The electronic components are coded with their respective part number. Each component has its own datasheet which explains the part’s features and specifications. Here are some of the well-known component distributors who can help you find the right components:

  • Mouser
  • DigiKey
  • Arrow
  • Avnet
  • Element14

Electronic Component Manufacturers

Below are a few well-known components manufacturers:

  • Molex
  • Intel
  • ROHM Semiconductor
  • Texas Instruments
  • Analog Devices
  • NXP
  • Maxim Integrated
  • Infineon
  • Amphenol
  • Sensirion
  • Microchip Technology
  • TE Connectivity