One key factor that differentiates types of electronic components from each other is whether they are passive or active. However, many people are unsure of exactly what that difference entails.
Difference Between Active and Passive Components
What are active components? These components are parts of a circuit that rely on an external power source to control or modify electrical signals. Active components such as transistors and silicon-controlled rectifiers (SCRs) use electricity to control electricity.
What are passive components? Like resistors, transformers, and diodes don’t need an external power source to function. These components use some other property to control the electrical signal. As a result, they only require the current traveling through the connected circuit. Resistors impede the flow of electrons without introducing more electricity into the system.
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Active and Passive Components in Electronics
While their superficial differences are easy to articulate, active and passive components tap into a more fundamental premise of electronics design: the conservation of energy. Because energy cannot be created or destroyed, and real-world machines cannot operate at 100% efficiency, all real-world passive circuits will lose some amount of power in use. We witness this net loss through the decline in power between the input and output signals and a decrease in amplification.
In practical terms, active components are useful because they often enable a small amount of electricity to control a larger quantity. In other words, one of the major benefits of active devices like transistors, tunnel diodes, and vacuum tubes is that they allow amplification. Whether they influence the flow of electricity by using voltage or current as the control, active components allow a small input to generate a matching, larger output.
Electronic Components Explained
Active components such as amplifiers, vacuum tubes, and transistors make use of an external power source to add power to a system. They use one electrical signal to control another and are required for the circuit to be considered “electronic.” Technically, we don’t define circuits without active components as “electronics,” but in practice, virtually all electronic circuits have passive components as well. Passive components like resistors, inductors, and capacitors influence the flow of power but do not require an external power source to function.
You will likely find both kinds of components in every electronic device.
