## Difference between Positive and Negative Feedback loop

In our previous article, we discuss the difference between open and closed loop control systems. The closed loop system comprises feedback. The feedback can be positive or negative depending upon the application. Let see what is the difference between positive and negative feedback loop control system. The main difference between the two is that in … Read more

## Difference between Open loop and Closed loop Control System

A control system can be classified as open loop control system and closed loop control system. There is a lot of confusion among people regarding these two types of control system. In this article, we will discuss what is the difference between open loop and closed loop control system based upon factors such as construction, … Read more

## Controllability and Observability in Control System

Controllability and Observability is an important concept of the state space representation of a system that we read in the control system. In this article, we will learn how to check the system’s controllability and observability. Controllability Definition If the state of the system can be transferred to another desired state over a finite time … Read more

## Parseval’s theorem Proof

In this article, we will see Parseval’s theorem proof. Before we go any further, first learn What is Parseval’s theorem? It states that the sum (or integral) of the square of a function is equal to the sum (or integral) of the square of its transform. Parseval’s theorem is also known as Rayleigh’s energy theorem or Rayleigh’s Identity … Read more

## Controllers – Proportional, Integral & Derivative Controllers

In control engineering, characterization of a controlled system is primarily determined by its dynamic behaviour which also characterizes the scope and the quality needed to solve a control task. The step response of the controlled system is used to reflect this dynamic behaviour. A controller is one of the most important parts of the control … Read more

Transfer function Definition A transfer function is expressed as the ratio of Laplace transform of output to the Laplace transform of input assuming all initial condition to be zero. Consider a system whose time domain block diagram is   where, r(t) = input and c(t) = output Now taking Laplace transform then Now the transfer … Read more

## Control System Basics

Our daily activities are getting automated every day. Control System plays an important role in making our life automated and modernized. A microwave, refrigerator, an air conditioner, a geezer, an automatic iron, are some examples of a control system. Many engineering fields use control system principle in many applications.   System It is an interconnection … Read more

## Proportional-Integral (PI) Controllers

Proportional-Integral (PI) controllers are used in many industrial control applications. The main purpose of using Proportional and Integral (PI) in process system is to improve the steady-state accuracy of the system without affecting the stability of the system. Proportional action responds quickly to the error deviation and the integral action will act slowly but offset … Read more

## Frequency Domain Analysis – Advantages

Frequency Response The Frequency Response of the system is the steady-state response of the system obtained as the output when a sinusoidal input signal is given to the system. For determining the frequency response of a control system sinusoidal signal is given as input to the system with different frequencies and response of the output … Read more

## Proportional (P), Integral (I), Derivative (D) Controllers Usage Conditions

1. When does the Proportional (P) Controller is used? Answer. Proportional (P) Controller is used during the following conditions: Load Changes are small Offset (error exist due to difference between steady state value and desired value) can be tolerated. The process reaction rate is such as to permit a narrow proportional band. Since this reduces … Read more