# Active and Passive Elements – Basic Explanation

If the equations are not displayed correctly, please use the desktop view

Contents

Active and passive elements are very important for us electrical engineers. What are those actually?

Just like its name, an element is a part of something. This element along with another element will build something we plan. Furthermore in an electrical circuit, active elements and passive elements will build an entire electrical circuit we desire.

It is almost impossible to build an electrical circuit with active elements alone or passive elements alone.

For starters,

An active element is capable of delivering energy to an electric circuit, while a passive element is an element that is not capable of generating power.

How and why those two are defined, we will learn it fully in this post.

One thing to remember, active and passive elements are the foundation of an electrical circuit. Learning the difference between those two will help us greatly when designing, fixing, and building a circuit.

## What are Circuit Elements

A circuit element is an electrical device that affects voltage-current relationship in an electrical circuit.

They have their own voltage-current characteristic to make them able to change the voltage-current in the circuit as we desired.

When talking about circuit elements, most of you will mention electrical components such as resistor, capacitor, inductor, diode, etc. They are indeed the elements we need to build an electrical circuit.

Since there are a lot of electrical components, we can still categorize them into several circuit elements based on their characteristics.

Rather than mentioning the elements, it is easier to mention the types of circuit elements. Every element in the same type mostly shares the same characteristic with some difference in specifications and shapes.

We can list the types of electrical circuit elements below:

• Circuit element ports,
• Circuit element linearity, and
• Active and passive elements.

We will focus on active and passive elements, but knowing the first two types briefly won’t cost us anything since they are also related to the active and passive elements.

## Circuit Element Ports

We can divide the circuit element by their number of ports, such as:

• One-port elements: this type of element is the simplest one. This element only has two terminals which can be connected with another element. The examples of this type are resistors, inductors, and capacitors.
• Multi-port elements: unlike one-port elements, this type has more than two terminals. These elements connect to circuits with multiple terminals (ports). An example of this type is a 3-winding transformer (6 ports).

## Circuit Element Linearity

This type will divide circuit elements into linear and nonlinear elements.

Linear elements

This type of element follows the linearity between voltage and current even if the phase is shifted. The examples of this type are resistor, inductor, capacitor, and dependent source. The main idea is that the output waveform is the same with the input waveform regardless of the magnitude and the phase.

These elements will not cause distortion and can be analyzed easily. The examples of linear components are resistor, capacitor, and inductor.

Below is an example of linearity of a resistor. Below is an example of linearity of an inductor. Below is an example of linearity of a capacitor. Nonlinear elements

This type of element will follow the nonlinear relationship between voltage and current. This element will cause distortion and the example of it is a diode. You will find it harder to analyze this type of element. But it doesn’t matter, we don’t need to understand it right now.

## Active and Passive Elements

If you wonder what the most common types of circuit elements are? Well, we will talk about active and passive elements. What is the difference between these two? These two types of element will form the node, branch, and loop to make a complete circuit.

Active elements and passive elements will connect to each other with the help of conductor wires to form nodes, branches, junctions, and loops. All of these will form a complete electrical circuit.

So, what are active and passive elements?

The definition of active and passive elements is the elements that build an electrical circuit by generating, absorbing, and converting electrical energy.

One thing to remember, their difference lies in the capability of generating energy. Active and passive elements are a serious matter to analyze in a circuit. These elements will take part in Ohm’s law explanation in a later post.

## Active Elements

Active elements can be used for electrical power sources, such as voltage source and current source.

Active element is capable of producing electrical power and its role is to amplify an input signal to be a larger output signal.

The examples of active elements are voltage source, current source, transistor, diode, and generator.

What are active elements?

An active element is an electrical component which is capable of delivering energy to an electric circuit.

An active element in a circuit is one which supplies electrical energy to the circuit.

From the active elements definition above we can say that active elements have the capability of controlling electrons flow. We need at least one active component to make a circuit work.

The most important active elements examples are voltage and current source. These two are able to deliver power to the circuit.

The voltage and current source can be divided again into 2 types: independent sources and dependent sources. We will learn this in the next session.

## Passive Elements

Passive elements are often used as a load for a circuit. Its capability of storing energy, resisting voltage or current, and absorbing energy gives us a huge choice on designing an electric circuit.

The most basic passive elements are resistor, capacitor, and inductor. While we can divide the resistor into resistor in series or resistor in parallel. We can do the same with the capacitor and inductor.

What are passive elements?

Passive elements are elements that are not capable of generating power. But, this element absorbs, stores, or dissipates energy flowing to it.

A passive element in a circuit is one which absorbs and converts electrical energy.

From the passive elements definition above we can say that passive elements do not have the capability of controlling electrons flow. We need at least one passive component to prevent short circuits and generate an output.

This element can be represented as a load. The most basic passive elements examples are resistor, inductor, and capacitor.