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Electrical And Electronic Engineering Course Materials

U# Electrical-And-Electronic-Engineering-Course-Materials Electrical And Electronic Engineering Course Materials-- Books , Class Lectures,source code

Power System

Electronic Engineering

Communication Engineering

vlsi

Biomedical Engineering

Power Electronic

Industrial Automation

Programmable Logic Designr

Solid State Device

Circuit Integration

Electronic Project

Digital signal processing

Analog Signal Processing

Linear System

Materials Engineering

PCB Design Report

Linear System at DE

Industrial Automation

Matlab Course

Circuit design using orcad

Power Electronic Part 2

electrical-and-electronic-engineering-course-materials's Issues

Closed loop control system

A closed loop control system is a system in which control action is dependent on the desired output. In this system, the output signal is compared with the reference input signal, and an error signal is produced then this error signal is fed to the controller to reduce the error to obtain the desired output.

control systems Introduction
Examples
Automatic electric iron.
Servo voltage stabilizer.
An air conditioner.
Advantages of closed-loop systems
These systems are more reliable.
Closed-loop systems are faster.
Many variables can be handled simultaneously.
Optimization is possible.

Classes of signals on the basis of their power and energy:

Energy signal– generally converging signals, aperiodic signals or signals that are bounded.
$$ E < \infty\ and\ P=0 $$

Power signal– generally periodic signals, as they encompass infinite area under their graph and extend from +\infty to -\infty.
$$ E \rightarrow \infty\ and\ P=constant $$

Neither energy nor power signal
$$ E \rightarrow \infty\ and\ P \rightarrow \infty $$

Medical Electronic

Medical Electronics Engineering that advances knowledge in Engineering and Medicine is one of the most extensively growing fields of this era where people prefer the best and precise health service. Medical Science examines treats and cures almost all the disease meeting the need of accuracy by the people by using sophisticated and precise equipments. A medical electronics engineer can be called as the doctor of the equipments without which a doctor, a surgeon or a multi specialty hospital is helpless. He/She is the person, who knows the mechanism, operation and maintenance of these equipments.

Power Amplifiers

The Small Signal Amplifier is generally referred to as a “Voltage” amplifier because they usually convert a small input voltage into a much larger output voltage. Sometimes an amplifier circuit is required to drive a motor or feed a loudspeaker and for these types of applications where high switching currents are needed Power Amplifiers are required.

As their name suggests, the main job of a “Power Amplifier” (also known as a large signal amplifier), is to deliver power to the load, and as we know from above, is the product of the voltage and current applied to the load with the output signal power being greater than the input signal power. In other words, a power amplifier amplifies the power of the input signal which is why these types of amplifier circuits are used in audio amplifier output stages to drive loudspeakers.

Transformation of the independent variable:

Shifting- the signal can be delayed ( x(t-T) ) or advanced ( x(t+T) ) by incrementing or decrementing the independent variable (time here).
The shape of the graph remains same only shifted on the time axis.

Scaling- the signal can be compressed ( x(at), a>1 ) or expanded ( x(t/a), a>1 or x(at), 1>a>0 ).
Here the shape/behaviour of the graph of the signal changes as the fundamental time period changes. In compression the time period decreases and in expansion the time period increases.

Reversal- also called folding as the graph is folded about the Y-axis or T if given x(T-t).

About Amplifier

An amplifier is a circuit that has a power gain greater than one. An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment.

What is control engineering?

Control engineering is also referred to as control systems engineering. It’s a discipline in engineering that uses control theory to design and develop systems and is related to mechanical and electrical engineering.

Control engineering is key in many user control systems that range from a simple dishwasher to an airplane. These systems are designed to function with minimal or even zero human intervention. (E.g., cruise control in auto vehicles).

Linear and Non-linear system

Linear system: A system is known as linear if and only if it possesses both homogeneity and superposition properties. Superposition implies that an input r1 (t) gives an output c1 (t) and another input r2 (t) gives the output c2 (t). If two inputs are applied together then the output will be the sum of two outputs:

r1(t) + r2(t) = c1(t) + c2(t)
If our input-output relationship is a straight line passing through the origin, then the system obeys the superposition property. The straight line passing through origin means that the output is zero (0) for zero (0) input.

If the input increases for any system K time from r1 (t) to Kr1 (t) then the magnitude of the output is also increased from c1 (t) to Kc1 (t) then this property is known as homogeneity. This property is a necessary condition for a system to be linear.

Open loop control system

An open-loop control system is a system in which the control action is independent of the desired output signal. In this system, the output signal is not compared with the input signal which means there is no feedback signal in this system. The open-loop control system is also known as a non-feedback control system or control system without feedback.

Signal System

Signal is an electric or electromagnetic current carrying data, that can be transmitted or received.

Mathematically represented as a function of an independent variable e.g. density, depth, etc. Therefore, a signal is a physical quantity that varies with time, space, or any other independent variable by which information can be conveyed. Here independent variable is time.

Types of time signals:

Continuous time signals x(t)- defined at every point in time
Discrete time signals x[n] – defined only at a discrete set of values of time (integer).
A System is any physical set of components or a function of several devices that takes a signal in input, and produces a signal as output.

Classification of Control System

The control system may be classified in a number of ways. Some popular classifications are:

Depending on the methods analysis and design, the system can be linear or non-linear.
Depending upon the type of signals, the system can be time-varying, time-invariant continuous data, discrete data, modulated or unmodulated control system etc.
Depending on the type of system component, the system can be electromechanical, biological, hydraulic, thermal or pneumatic control system etc.
Depending upon the primary purpose, the system can be position control, velocity control etc.

Continuous data and discrete data control system

In a continuous system, all system variables are the function of continuous time variable 't.' At any time't' they are dependent on time thus they are called continuous data control system.

In discrete data control system, if the signal is not continuously varying with time but it is in the form of pulses, the controlled system is called discrete data control system.

It is of two types

Sampled
Digital
If the signal is in the form of pulse data, the system is called a sampled data control system. The sampled form is shown in the below-drawn diagram.

Power Amplifier Gain

Note that for the Power Gain you can also divide the power obtained at the output with the power obtained at the input. Also when calculating the gain of an amplifier, the subscripts v, i and p are used to denote the type of signal gain being used.

The power gain (Ap) or power level of the amplifier can also be expressed in Decibels, (dB). The Bel (B) is a logarithmic unit (base 10) of measurement that has no units. Since the Bel is too large a unit of measure, it is prefixed with deci making it Decibels instead with one decibel being one tenth (1/10th) of a Bel. To calculate the gain of the amplifier in Decibels or dB, we can use the following expressions.

Voltage Gain in dB: av = 20log(Av)
Current Gain in dB: ai = 20log(Ai)
Power Gain in dB: ap = 10*log(Ap)
Note that the DC power gain of an amplifier is equal to ten times the common log of the output to input ratio, where as voltage and current gains are 20 times the common log of the ratio. Note however, that 20dB is not twice as much power as 10dB because of the log scale.

Also, a positive value of dB represents a Gain and a negative value of dB represents a Loss within the amplifier. For example, an amplifier gain of +3dB indicates that the amplifiers output signal has “doubled”, (x2) while an amplifier gain of -3dB indicates that the signal has “halved”, (x0.5) or in other words a loss.

The -3dB point of an amplifier is called the half-power point which is -3dB down from maximum, taking 0dB as the maximum output value.