Passive Components in Electrical Circuits

In electronic components, Passive components are electronic devices that don’t need an external power source to operate actively. They do not generate power rather they store and release it. They mainly resist, store, or control the flow of electric current or voltage in a circuit without actively amplifying or generating signals. Passive components include resistors, capacitors, inductors, diodes, and coils – that don’t require power to do their job.

A circuit is an interconnection of elements. Based on their capability to generate energy these elements are classified into active or passive elements. Electric circuits are made up of three circuit components. These are resistance, inductance, and capacitance. These are called passive circuit elements and they do not transfer electrical energy. Passive elements stores energy in the form of voltage or current.

What are Passive Components?

Passive components are electronic devices that don’t need an external power source to operate actively. They mainly resist, store, or control the flow of electric current or voltage in a circuit without actively amplifying or generating signals.

Passive components can be used to connect together within the circuit in a series combination or parallel combination to control the current flow in complex circuits. Passive components do not require any external power supply to operate in the electrical circuit. Passive components receives the electrical energy and either convert it or store in the form of magnetic field or electric field. Passive components do not require any electrical power to function in a circuit. Passive components cannot increase the power of a signal nor are they able to amplify in the circuit. So basically, they do not generate power , they dissipate power only.

Properties of Passive Components

• Passive electronic components do not generate electrical power. They only dissipate power (in resistive components) or store unused power (in reactive components). 
• All passive electronic components function without a power source. They only influence the flow of power and the electrical output cannot be modified by some external power source.
• Passive components act as load in the circuit.
• Passive components cannot provide power gain.
• Passive components receive electrical energy and either convert it into other forms such as heat, light, rotation, etc., or store it in the magnetic field or electric field.
• Passive components cannot control the current flow in the circuit.
• A passive element can only absorb electrical power. It is not capable of delivering power.

Working of Passive Components

The circuit element that can only absorb electrical energy and dissipate it in the form of heat or stored in either magnetic field or electric field is known as passive circuit component or passive component.

Working of Passive components includes, passive components receiving electrical energy and either converting it in other forms such as heat, light, rotation, etc., or store in the magnetic field or electric field. These passive components act as loads in the circuit.

Therefore, a passive component cannot provide electric power or power amplification in an electric circuit. Some common examples of passive circuit components are resistors, inductors, capacitors and transformers, etc.

Types of Passive Components

Passive components are mainly divided into four basic passive electronic components which include:

• Resistor
• Capacitor
• Inductor
• Transformer

Resistors

Resistors control the flow of current by offering resistance. They are used to limit current, divide voltage, and set biasing conditions in electronic circuits.

• Resistors oppose the flow of electrical charge or electrical current.
• Resistance is measured in ohm.
• The opposition to the flow of electrical current through the material is known as the resistance of that material.
• Resistors are made up of materials like Tungsten, Bronze, and Constantan.

Resistor voltage equation:

V= I x R

• where V stands for Voltage
• I stands for Current
• R stands for Resistance

Applications of Resistors

• It is used in Potential Divider.
• It helps in Biasing Circuits.
• It is used in Feedback Networks.
• It is used in Amplifiers.
• It is used in Current controlling devices.
• It is used in Coupling Networks.
• It is used in DC Power Supplies.

Capacitors

Capacitors store and release electrical energy. They are commonly used for decoupling, filtering, and energy storage in electronic circuits.

• It is used to pass AC and block DC.
• It opposes the flow of direct current.
• It consists of two conducting parallel plates separated by dielectric.
• Dielectric is made up of ceramic, mica, glass, waxed paper, and bakelite.

Capacitor current equation with respect to time:

[Tex]I(t) = C \frac{dV(t)}{dt} [/Tex]

• I(t) stands for current in capacitor with respect to time
• C stands for capacitance
• V(t) stand for voltage across the capacitor with respect to time t.

Capacitor (Passive Component)

Applications of Capacitors

• It is used for storage of energy.
• It is used in filter circuits to minimize the repel voltage.
• It is used in tunning circuits for selection of frequency.
• It is used in timing circuits to select the time.
• It is used in Amplifiers.

Inductors

Inductors store and release magnetic energy. They are used for applications such as filtering, energy storage, and impedance matching.

• All inductors are coiled structures and insulated wire wrapped around the area.
• Inductors work on electromagnetic induction.
• It is used to decrease the electric spikes in electronic circuits.

Inductor Current equation with respect to time:

[Tex]V(t) = L\frac{di(t)}{dt} [/Tex]

• V(t) stand for voltage across the inductor with respect to time t
• L stands for inductance
• i(t) stand for current through the inductor with respect to time t

Applications of Inductors

• It is used in minimizing alternating current in the circuits.
• It is used in RF choke in the oscillator.
• It is used in LC resonance.
• It is used in Radio Transmitter and receiver.

Transformers

A transformer is also a passive electronic component. A transformer is used to transfer electrical power from one circuit to another via magnetic media i.e. magnetic core.

• It has two windings on a core. The winding to which input power is given is called the primary winding.
• The winding which delivers power to the load is the secondary winding.
• When transformers step up or step down voltage, power, and energy remain the same on the primary and secondary sides. As energy is not being amplified.
• Transformers are often used to raise voltage levels and keep the power constant.

Transformer current Equation

[Tex]\frac{I1}{I2} =\frac{N2}{N1} [/Tex]

• I₁ stands for primary current in transformer
• I₂ stands for primary current in transformer
• N₁ stands for number of turns in primary winding
• N₂ stands for number of turns in secondary winding

Transformer (Passive Component)

Applications of Transformers

• It is used to raise voltage levels.
• It is used in power generation
• It is used in transmission and distribution.
• It is used in lighting, audio systems, and electronic equipment.

Other Passive components include diodes, thermistors, varactors, transducers, and many other common components. These components are available as through-hole and components, and many are available in common packages with standard land patterns.

Difference Between Active and Passive Components

Active Components	Passive Components
Active Components require an external power supply to operate in the circuit.	Passive Components do not require external power supply to operate in the circuit .
Active Components produce energy in form of current or voltage.	Passive Components store energy in form of current or voltage
Active components can power gain in the electric circuit.	Passive components cannot provide power gain in the electrical circuit.
Active components can control the flow of current.	Passive components cannot control the flow of current
Active components receive energy in the forms of thermal energy, chemical energy, hydraulic energy, and delivers in the circuit in the form of electrical energy.	Passive components receive electrical energy and either convert it or store in the form of magnetic field or electric field.
Examples of Active Components are semiconductors, diodes and transistors.	Examples of Passive Components are resistor, inductor, capacitor and transformers.
Active components are energy donors.	Passive Components are energy acceptors.

Advantages and Disadvantages of Passive Components

There are some list of Advantages and Disadvantages of Passive Components given below :

Advantages of passive components

• Passive components can store energy.
• Passive components can provide power conversion.
• Passive components offer isolation.
• No extra power supply needed from outside.
• They are available at low cost.
• Passive components are easy to design.

Disadvantages of Passive Components

• Sometimes they have response issues.
• They provide less functionality.
• We have less control on passive components.
• Passive components cannot amplify the signal in the circuit.

Conclusion

In this article we have learnt about Passive components, these can easily handle energy in the electrical circuit by storing it in the form of a magnetic or electric field or converting it into some other form of energy. We have seen the properties of passive components and different types of passive components and we have the applications and advantages and disadvantages of passive components. In Electrical circuits, passive components play an important role in storing and handling energy in the electrical circuits.

FAQs on Passive Components – Electrical Circuits

1. What are the classification of passive components?

The components which cannot control the flow of current in any circuit are called passive components. Resistors, capacitors, inductors, transformers, etc. are classified into passive components.

2. What are the types of electronic components ?

Electronic components are mainly classified into two types:

• Passive components
• Active components

3. What are the characteristics of active components ?

The characteristics of active components include:

• They can control the electric current flowing through them.
• They depend on the external voltage or current to work.
• They amplify the power of an electrical signal