In electronics, components are classified as either active or passive.
Active components are those that can control the flow of current and have the ability to amplify or generate electrical signals. Examples of active components include transistors, integrated circuits (ICs), diodes, and vacuum tubes. Transistors, for instance, can amplify weak electrical signals, making them stronger. Integrated circuits contain multiple transistors and other components on a single chip and perform complex functions. Diodes allow current to flow in only one direction and are used in rectification and signal processing.
Passive components, on the other hand, cannot amplify or generate electrical signals. They simply store, dissipate, or resist electrical energy. Common passive components are resistors, capacitors, and inductors. Resistors limit the flow of current and control the voltage in a circuit. Capacitors store electrical charge and are used for filtering and timing purposes. Inductors store energy in a magnetic field and are often employed in filtering and power supply circuits.
For example, in an audio amplifier circuit, transistors are the active components that amplify the audio signal, while resistors and capacitors are the passive components that set the gain, filter frequencies, and stabilize the circuit.
Understanding the difference between active and passive components is essential for designing and analyzing electronic circuits.