Difference between Active and Passive Components
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All the electronic components can be broadly classified into two main classes- Active components and passive components. Active components are those circuit elements that deliver energy or power to the circuit while passive components are the ones that utilize the power or energy in the circuit. Active components require an external source to operate while passive circuit elements don’t require an external source for their operation. In this article, we will see the exact difference between active and passive components.
Active vs Passive Components – Comparison Table
Now let’s see the difference between active and passive components with the help of the following table.
| Basis of Comparison | Active components | Passive components |
| Power delivered or required | Active components provide energy or power to the electrical circuit in the form of voltage or current. | Passive components utilize or store the energy in the form of current or voltage. |
| Requirement of an external source | Active components require an external source for their operation. | No external source is required for passive components to operate. |
| Flow of current | Active components can easily control the flow of current. | Passive components do not exhibit the property to control the flow of current. |
| Linearity | Active components are non-linear which means the voltage drop across will not vary linearly with the current. | Passive components are linear which means the voltage will vary linearly with the current according to Ohm’s law. |
| Power gain | Active components are capable of providing power gain. | Passive components do not possess the ability to amplify power. |
| Examples | Diodes, transistors, Silicon Controlled Rectifiers (SCRs), and op-amps are some of the examples of Active components. | Resistor, Capacitor, Inductor are examples of Passive components. |
Now since we have compared the active and passive components, let’s dive into the basics of active and passive components.
What are active components?
Active components are the ones that have the ability to provide or deliver energy to the circuit in the form of voltage or current. They can amplify an electrical signal and produce power. They require an external source for their operation. They will keep on providing power to the circuit for an indefinite time period till the presence of an external supply source.
Now let’s understand how these active components require external power to initiate the operation.
Let’s take the example of a diode, a diode starts working only when a voltage greater than its potential barrier is provided to it. For example, a silicon diode requires at least 0.7 V to conduct the current in the circuit. So here we require an external source to initiate the operation.
They are nonlinear devices which imply that the voltage across them doesn’t linearly depend on the current across them. Since these elements provide energy or power to the electrical circuit, they act as generators. Active components also possess the ability to control the flow of current in the circuit, that’s why they are also known as current-controlled devices. They are energy donors.
A few examples of active components are diodes, transistors, Silicon Controlled Rectifiers (SCRs), Integrated Circuits.
Let’s have a look at the basics of these devices:
Diode
It is an active component that is used to direct the flow of current in only one direction.
Transistor
A transistor is a three-terminal device that has the capacity to amplify an input signal. Transistors utilize the power from an external source and supply it to the electrical circuit to which they are connected, which is a characteristic of an active device.
What are passive components?
Passive components are the devices or elements that utilize energy in an electrical circuit. Unlike active components, these are used to store or utilize the energy in the form of voltage or current. These are not able to provide any gain.
These elements do not need an external source to operate or function. Passive components can not control the flow of current in the circuit. These devices are energy acceptors.
Passive components are linear devices which means that the voltage drop across them varies linearly with current according to Ohm’s law, like in the case of a resistor. Since Passive components are bidirectional in nature they can be connected in either direction in the circuit. They work as attenuators due to their ability to store or dissipate the power.
A few examples of passive components are Resistor, Capacitor, Inductor.
Conclusion
From the above discussion, we have concluded that although they are a part of the same circuit, they have different functions to perform in the circuit. Active components provide power to the circuit while Passive components utilize or store that energy or power. Active components require an external source of power to operate. On the other hand, passive components don’t need any source of power, they can work on their own.
We have compared the difference between active and passive components and have also explained the two in great detail.
Author
Deepak Yadav
Aligarh Muslim University, Aligarh
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