Active Component may refer to:

• Active duty, a full-time occupation as part of a military force, as opposed to reserve duty.
• "Active Components", now "Active Tech", an industrial electronics retail part vendor formerly part of Future Electronics.
• In electronics, active components are devices (such as valves or transistors) with the ability to amplify a signal or produce a power gain.

Passivity is a property of engineering systems, used in a variety of engineering disciplines, but most commonly found in analog electronics and control systems. A passive component, depending on field, may be either a component that consumes (but does not produce) energy (thermodynamic passivity), or a component that is incapable of power gain (incremental passivity).