What is the difference between active and passive components?

• A. Active components are energy-saving devices
• B. Active components can control electric current, while passive components simply react to it
• C. Active components have no effect on current
• D. Active components are only used in AC circuits

Answer: (B)

Active components are defined by their ability to control the flow of electric current, whereas passive components do not have this capability. Active components, such as transistors and operational amplifiers, are able to provide energy gain or control current flow in a circuit, thus influencing how the circuit operates. They can introduce energy into the system, typically in the form of power supply connections, and can amplify, switch, or process signals.

In contrast, passive components—like resistors, capacitors, and inductors—cannot control current. They react to the current that flows through them, either by resisting it, storing energy, or releasing it, thereby affecting the circuit behavior without adding energy. This fundamental characteristic distinguishes the two types of components, making the understanding of their roles essential in electrical engineering and circuit design.