Memristor-The Missing Passive Element

Hello guys, it has been a very long gap I’m posting another interesting post, its time to know something different which most of the people doesn’t know.  Its time to know one of the interesting element which led the advancement of electronics, which made robotics more efficient, a passive element which many people doesn’t know, yes it’s the 4^th element of the passive elements family called “ Memristor” .

Memristor

This post presents a very brief description of the special two terminal device named ‘Memristor’, a contraction of Memory and Resistor which has every right to be as a basic as the three classical circuit elements already in existence, namely, the resistor, inductor, and capacitor.

The concept of memristor was originally proposed by a circuit theorist LEON.O.CHUA in 1971 as a missing nonlinear passive two terminal component relating the charge q(t) and the flux-linkage ψ(t) As per many circuit theoretic properties of memristor derived, it is shown that this element exhibits some peculiar behaviour different from that exhibited by resistors, inductors, or capacitors. These properties lead to a number of unique applications which cannot be realized with RLC networks alone.

Curve relating charge & flux linkage

The memristor's resistance is not constant but depends on the history of current that had previously flowed through the device, i.e., its present resistance depends on how much electric charge has flowed in what direction through it in the past. The device remembers its history, that is, when the electric power supply is turned off, the memristor remembers its most recent resistance until it is turned on again.

Applications of Memristors:

v The memristor could make it possible to develop far more efficient computing systems with memories that retain information even after the power is off, so there's no wait for the system to boot up after turning the computer on.

v  It may even be possible to create systems with some of the pattern-matching abilities of the human brain.

v As for the human brain-like characteristics, memristor technology could one day lead to computer systems that can remember and associate patterns in a way similar to how people do.

v This could be used for improving face recognition technology & biometric technologies.

v Solid state memristors can be combined into crossbar latches which may replace transistors in the future.

v These have applications in the various fields of electronics such as signal processing, control systems, radio frequency identification and so on….

Hope this brief idea about the Memristors was useful to all , hoping to write more regarding this in the upcoming future. Thanx for visiting the blogger. Do comment ur views . Keep visiting..

IGBT

Hi guys today we shall go through one of the most popular power semiconductor devices “IGBT”.

As we all know, the power semiconductor devices have become more popular in the recent past the power semiconductors can be broadly classified into three categories.

•        Power diodes
•        Power thyristors
•       Power transistors

The device which we are discussing today comes under the last category “Power Transistors”.

First of all we shall discuss about the basic symbol of IGBT

What does IGBT stand for ? and what is its symbol?

The IGBT is the abbreviation of Insulated gate bipolar transistor, which is the latest device in power electronics. It is obtained by combining the properties of BJT and MOSFET. We all know that BJT has low on-state losses for higher values of collector current but the drive requirement is complicated. The drive of the MOSFET is very simple but has high on-state losses. Hence the gate circuit of the MOSFET and the collector emitter circuits of the BJT are combined together to form a new device called IGBT thus the IGBT has the advantages of both BJT and MOSFETs.

Symbol of IGBT:

The above image shows the symbol of the IGBT, it has three terminals : Gate(G), collector(C ), Emitter(E) . Current flows from collector to emitter whenever a voltage between gate and  emitter is applied. IGBT is said to be turned on if gate voltage is applied else turned off hence the gate has full control over the conduction of IGBT.

Structure of IGBT:

The P⁺ injecting layer is heavily doped. It has the doping intensity of10¹⁹ / cm³. The n⁺ layer has 10¹⁹ / cm³. P type body region has doping level of 10¹⁶ / cm³and the n^- layer is lightly dope with 10¹⁴/ cm³.

Punch through IGBT: the n⁺ buffer layer is not necessary for the operation of IGBT. The IGBTs which have n+ buffer layer are called punch through IGBTs. Such IGBTs have asymmetric voltage blocking capabilities. These have faster turn off times hence used in inverters and choppers.

Non-punch through IGBT: The IGBTs without n⁺ buffer layer are called non-punch through IGBTs. These IGBTs have symmetric voltage blocking capabilities. These are used for rectifier type applications.

VI characteristics of IGBT:

Hope u all enjoyed it :) keep visiting!!

PLC

Hi friends, today I’m going to give info about PLC. 

A PLC is the acronym of Programmable logic controller. The advent of the PLC began in the 1970s and today in the world of automation; the PLC has become a standard for control. Control engineering has evolved over a long period of time. In the past, humans were the main for controlling a system. As the technology developed electricity has been used for control. One such is relay which allows power to be switched ON & OFF without a mechanical switch. The development of low cost computer has brought the most recent revolution called PLC.

Block diagram of PLC

What a plc is?

A PLC is a user friendly microprocessor based circuit that is used to conduct multiple and complex operations. 

• A PLC is essentially microprocessor or microcontroller based. It has multiple inputs and outputs. It functions according to the software.
• PLC monitors crucial process parameters and controls the process operations accordingly. 
• The PLC replaces much complicated wiring by a single circuit. 
• The input to the PLC can also be taken from analog devices or discrete (on off) devices. 
• The PLCs have tremendous computing capacity but at the same time its size is very compact. 
• Ladder Diagram is primarily used to develop software for programmable logic controllers (PLCs) used in industrial control applications.

Now let’s see what are the advantages of the PLC system:

• PLCs are highly flexible. 
• They have compact size and reduced cost. 
• PLCs are accurate, high speed and reliable. 
• PLCs can be reprogrammed easily & quickly. 
• Data storage and logging is easier since PLCs can be easily interfaced to computers. 
• PLCs can handle large number of inputs and outputs. 
• Programming of PLCs is easier. 

Disadvantages: 

•  For small operations or one or two functions, PLCs are not cost effective. 
• PLCs use electronic devices and microprocessors. They fail sometimes in adverse environmental conditions. 
• If operation is never altered, PLCs prove to be costly.

A few examples of ladder diagrams are:

Ladder diagram for Stair case controller

I hope u all enjoyed this…. Keep visiting!!

Waveguides

Today we shall concentrate on one of the Transmission media called wave guides. A hollow conducting tube to transmit electromagnetic waves is termed as wave guide. A waveguide is a hollow tube designed to carry microwave energy from one place to another place. Waveguides may be used to carry energy between pieces of equipment or over longer distances. Waveguides are made from copper, aluminum or brass. These metals are extruded into long rectangular or circular pipe

The electric and magnetic fields of electromagnetic wave are confined to the space within the guide and made to propagate down the length of the wave guide.

Characters of waveguides:

• The propagation takes place through the dielectric field.
• Propagation is in terms of electric and magnetic fields rather than voltage and currents.
• The electric and magnetic fields that exist inside the waveguide are solution of Maxwell’s wave equation.
• Each waveguide has cut off frequency that decides the dominant mode of propagation.

Coming to the types of waveguides. There are three types of waveguides namely:

1. Rectangular waveguide:

     2.circular (cylindrical) waveguide:

     3.Ridged waveguide:

Advantages of waveguides:

• The waveguides can be used at much higher frequencies than the co-axial cables.
• Easy to manufacture than co-axial cable because waveguides are hollow.
• Waveguides do not have either inner conductor or dielectric material, therefore power handling ability is improved. It is about 10 times as high as for co-axial air dielectric rigid cables.
• Power losses are less.
• There is no radiation loss.

Applications:

• They are at their supreme in microwave transmission.
• Used to connect Radar transmitter to antenna.
• Used to channel the received echo to the receiver from the antenna

INTEGRATED CIRCUIT

Hi friendz today we shall have some knowledge about integrated circuits (abbreviated as IC).Before knowing the definition of ICs we shall know why an IC was developed?

 Now a days integrated circuits are more popular. In the early days some discrete components like capacitor, resistor, diodes, were used to be connected in a definite pattern(using wires) called electronic circuit. As the technology advanced the discrete components were integrated on a single chip this is called integrated circuit.

Integrated Circuit

Now coming to the definition : An IC is one in which a number of circuit elements like resistors, capacitors, transistors, diodes etc are fabricated on a small semi conductor chip to perform a complete function.

Classification of Ics:

1. Classification by Scale of integration:

·        SSI (Small scale integration) : ICs having 0 to 12 components on a single chip. Ex: Logic gates, Flip-flops.

·        MSI (Medium Scale Integration): Ics in this category contains 13 to 99 electronic components on a single chip. Ex: Adders, registers, encoders, multiplexers.

·        LSI (Large scale integration): Ics having 100 to 9999 components in a single chip comes under this category. Ex:Microcontroller, RAMs, ROMs

·        VLSI (Very Large scale Integration): Ics in this have 10000 to 99999 components in a single chip. Ex: Advanced microprocessor, Memory chips.

·        ULSI (Ultra Large Scale Integration): The components in the Ics of this type are more than 100000. Ex: Single chip Microprocessors, memory chips.

    

2. Classification by Structure:
• Monolithic
• Film Passive : Thick film and Thin film ics
• Hybrid Ics

3. Classification of Ics by function:

•           Analog Ics

Analog IC

• Digital Ics

Digital IC

Advantages of Integrated Circuits:

• Smaller weight.
• Low cost
• Highly reliable
• Low power consumption
• Easy replacement

Disadvantages of Integrated circuits:

·        Transformers, inductors can’t e fabricated.

• Large values of capacitance > 30pF can’t be built.
• The components in the IC can’t be repaired instead whole IC should be replaced.
• Not possible to modify circuit parameter

 Hope this was useful .. Keep visiting for exciting posts!!! 

Post ur opinions as comments!!!