Simply put, components that require a power supply (electric source) are called active components, while those that do not require a power supply are called passive components. Active components are generally used for signal amplification and conversion, whereas passive components are used for signal transmission, or in some cases, directional “amplification” of the signal.
Capacitors, resistors, and inductors are all passive components, while ICs and modules are active components.
(In layman’s terms, if a component needs power to exhibit its function—like a transistor—it is active. If it can perform its function without external power, it is passive.)
Simple Definition of Passive Components
If an electronic component does not contain any form of internal power during operation, it is called a passive component.
From a circuit behavior perspective, passive components have the following characteristics:
They either consume electrical energy or convert electrical energy into other forms of energy.
They only need an input signal and do not require an external power supply to function properly.
Basic Definition of Active Components
If an electronic component has an internal power supply during operation, it is called an active component.
From a circuit behavior perspective, active components have the following characteristics:
They also consume electrical energy themselves.
In addition to an input signal, they must have an external power supply to function properly.
Thus, active and passive components differ significantly in their working conditions and operational methods, and this distinction is very important when learning about electronics.
Common Passive Electronic Components
Passive components in an electronic system can be divided into two categories based on their function in the circuit: circuit-related components and connection-related components.
Circuit-related Components
(1) Diodes
(2) Resistors
(3) Resistor Arrays
(4) Capacitors
(5) Inductors
(6) Transformers
(7) Relays
(8) Push Buttons
(9) Buzzers, Speakers
(10) Switches
Connection-related Components
(1) Connectors
(2) Sockets
(3) Cables
(4) Printed Circuit Boards (PCBs)
Common Active Electronic Components
Active components are the primary devices in electronic circuits. Based on physical structure, circuit functionality, and engineering parameters, active components can be divided into discrete components and integrated circuits (ICs).
Discrete Components
(1) Bipolar Junction Transistors (commonly called BJTs or transistors)
(2) Field-Effect Transistors (FETs)
(3) Thyristors (also known as silicon-controlled rectifiers or SCRs)
(4) Semiconductor resistors and capacitors — manufactured using integrated technology, typically for use within ICs
Summary
Passive components mainly include resistive, inductive, and capacitive elements. Their common feature is that they can function with signal input alone, without needing an external power supply.
