How to Analyse the Cmos Buffer With Two transistors
This is one of the most prominent questions that is often asked in technical interviews of any electronics company.
This circuit seems like it is very simple,but it if you start solving it it will lead to hell.
In this post I will analyse this circuit and plot the VOUT vs VIN characteristics same as like the CMOS inverter.
I will give a few steps for users who are new.
step1:
Draw the Ids Vs vds Characteristics of PMOS.
Step2:
Draw the Ids Vs Vds charecteristics of NMOS.
Step3:
Overlap both the characteristics in a single plot.
Step4:
Find the Intersections Between the two plots for different values of Vgs.
These Values will give you the input and output values that are being satisfyied by the circuit. As it is very tuff to say intutively that which transistor will On and which will off for which values of input because those conditions will include the output voltage,I use MATLAB to get these graphs and intersections. The Matlab Code is given Below: clc; clear all; close all; vdd=5; up=500; un=1500; cox=3.28e-6; wbyl=2; wbylp=6; vtn=0.5; vtp=-0.5; vin=0:0.1:5; vout=0:0.01:5; lengthofvin=length(vin); lengthofvout=length(vout); for j=1:lengthofvin for i=1:lengthofvout if (vin(j)-vout(i)) < vtn currentn(j,i)=0; end if (vdd-vout(i))>(vin(j)-vout(i)-vtn)&& (vin(j)-vout(i))>=vtn currentn(j,i)=0.5*un*cox*wbyl*((vin(j)-vout(i)-vtn).^2); end if (vdd-vout(i))<=(vin(j)-vout(i)-vtn )&& (vin(j)-vout(i))>=vtn currentn(j,i)=un*cox*wbyl*(vin(j)-vout(i)-vtn-(vdd-vout(i))./2).*(vdd-vout(i)); end end end for j=1:lengthofvin for i=1:lengthofvout if (vout(i)-vin(j)) < abs(vtp) currentp(j,i)=0; end if (vout(i))>(vout(i)-vin(j)-abs(vtp))&& (vout(i)-vin(j))>=abs(vtp) currentp(j,i)=0.5*up*cox*wbylp*((vout(i)-vin(j)-abs(vtp)).^2); end if (vout(i))<=(vout(i)-vin(j)-abs(vtp)) && (vout(i)-vin(j))>=abs(vtp) currentp(j,i)=up*cox*wbylp*(vout(i)-vin(j)-abs(vtp)-((vout(i))./2))*(vout(i)); end end end hold on; plot(vout,currentp','b'); xlabel('--------->vds'); ylabel('--------->ids'); title('Ids Vs Vds'); plot(vout,currentn','r'); hold off; for j=1:lengthofvin count=0; for i=1:lengthofvout if currentn(j,i)==currentp(j,i) newinput(1,j)=vin(j); if(vout(i)<=abs(vtp)) newoutput(1,j)=abs(vtp); else if(vout(i)>=vdd-vtn) newoutput(1,j)=vdd-vtn; end newoutput(1,j)=vout(i); count=count+1; if count==1 break; end end end end end for j=1:lengthofvin count=0; for i=lengthofvout:-1:1 if currentn(j,i)==currentp(j,i) newoutput1(j,1)=vout(i); if(vout(i)>=vdd-vtn) newoutput1(j,1)=vdd-vtn; end count=count+1; if count==1 break; end end end end figure; hold on; plot(newinput,newoutput,'b',newinput,newoutput1,'b'); axis([0 5 0 5]); xlabel('--------------->vin'); ylabel('--------------->vout'); title('Transfer Characteristics');
The plot of the above MATLAB code will look something like give below:
So in the graph you can see that the intersection of the PMOS and NMOS curves for a particular value of VGS are the input and output voltages that will satisfy this circuit conditions.And from the above plot it is clear that we can see a lot of intersections between the PMOS and NMOS curves .So let us consider the average value of voltage between the first point of intersection and the last point of intersection between the two PMOS and NMOS curves for a particular value of VGS. Then we will get the input versus output characteristics as shown below.But still we have a confusion because we took an average intersection point .
If we take the first intersection point ,then we will get the characteristics like shown below:
1. Analogies used in the water flow model are as indicated
Valve 1 as Vg1
Valve 2 as Vg2
Source Width as Width
2.For the existing waterflow system as shown the two valve's are used for controlling the water flow, similar to the biasing voltages of an Amplifier.
Valve 1 is used for setting up the maximum distance the water can travel,which is similar to biasing the P MOS using VG1 with which Upper limit in output voltage is set.
3.Valve 2 is used to apply pressure on the waterflow which increases the distance with which water can travel.
Here the maximum distance is analogous to Overdrive voltage which is biased by making use Vg2 of N MOS.
4.Valve 2 is used to release pressure on the waterflow which decreases the distance with which water can travel.
Here the minimum distance is analogous to Overdrive voltage which is biased by making use Vg2 of N MOS.
5.Based on Minimum/Maximum distance travelled we can decide the Distance swing which is similar to the voltage swing.
6. Based on the source width variation we will have the water flow variation , which is analogous to the variation in width ,which varies current ,which varies the Gm and inturn varies the gain of the amplifier.
There at the Input pipe we can see the water flow with its pressure variation which is anologous to the applying a varying input voltage
The output is interms of travel distance variation of water ,which is analogous to the output voltage variations.
One of the most important question that is often asked in an interview(IT company)
These are all questions you've probably heard or even asked yourself. The term "cloud computing" is everywhere.
In the simplest terms, cloud computing means storing and accessing data and programs over the Internet instead of your computer's hard drive. The cloud is just a metaphor for the Internet. It goes back to the days of flowcharts and presentations that would represent the gigantic server-farm infrastructure of the Internet as nothing but a puffy, white cumulonimbus cloud, accepting connections and doling out information as it floats.
What cloud computing is not about is your hard drive. When you store data on or run programs from the hard drive, that's called local storage and computing. Everything you need is physically close to you, which means accessing your data is fast and easy, for that one computer, or others on the local network. Working off your hard drive is how the computer industry functioned for decades; some would argue it's still superior to cloud computing, for reasons I'll explain shortly.
The cloud is also not about having a dedicated network attached storage (NAS) hardware or server in residence. Storing data on a home or office network does not count as utilizing the cloud. (However, some NAS will let you remotely access things over the Internet, and there's at least one NAS named "My Cloud," just to keep things confusing.)
For it to be considered "cloud computing," you need to access your data or your programs over the Internet, or at the very least, have that data synchronized with other information over the Web. In a big business, you may know all there is to know about what's on the other side of the connection; as an individual user, you may never have any idea what kind of massive data-processing is happening on the other end. The end result is the same: with an online connection, cloud computing can be done anywhere, anytime.
With the latest research work coming out of University of Cambridge, their engineers seem to have found a breakthrough in electromagnetism. In the words the Cambridge Professor, Gehan Amaratunga, who led this research work, their findings could be the last missing piece in the puzzle of electronmagnetic theory. Developing antennas this small has been called the last frontier to be explored in the world of semiconductor design. If brought into practical use, this research could be a giant leap ahead for wireless connectivity. The engineering researchers working on this subject, recently published their results in the journal 'Physical Review Letters'. According to their study, they have put forward a concept that says - Electromagnetic waves are generated not only from the acceleration of electrons, but also from a phenomenon known as "symmetry breaking".
Not just in the field of wireless communications, but this discovery can also find implications in identifying the link between Electromagnetism and Quantum Mechanics. More than a 100 years ago, it was found that the radiation generated from electron acceleration resulted in electrons jumping from higher energy state to lower. However, this theory had no counterpart in quantum mechanics. With the latest observations of Cambridge University engineers, some insight about the radiation outputted due to electric field's broken symmetry may come forward.
In the last decade, the modern electronics has only made smaller and smaller devices. The size of these devices is reducing very rapidly and it seems that the antenna has not been able to cope with it. They are still very big in size and incompatible with electronic circuits. If the antennas are reduced in size, after a certain extent, their losses are too big. Engineers find it difficult to compromise wavelength for the transmission frequency of the application for the sake of reducing the antenna's size.
The electromagnetism theory that we know depends on acceleration of electrons. However, when electromagnets have to deal with radio wave emission from a dielectric solid, an insulating material, which doesn't let electrons move around freely. Even though that's the case, these dielectric resonators are already used as antennas in our smartphones. To understand the mystery behind how a dielectric medium results in emission of electromagnetic waves, the Cambridge team exposed thin films of piezoelectric materials to an asymmetric excitation and found that in addition to being efficient resonators, they became efficient radiators too. Therefore, it was found that they can be used as antennas as well.
In physics, 'symmetry' is a word used to signify a constant feature of a particular aspect in a system. When electrons aren't in motion, symmetry of electric field is established. The Cambridge researchers have determined that due to symmetry breaking of the electric field associated with the electron acceleration, their phenomenon exists.
Lastly, the team has shared the thin films of piezoelectric materials can be created using materials like lithium niobate, gallium nitride and gallium arsenide. What are your thoughts on this research work? Share with us in comments below.
Those of us who have used the face unlock system in smartphones have many times faced the problem where the system simply can't recognise the owner's photo. Though the face unlock system is present in Samsung Galaxy phones and it is really good at keeping most impostors at bay, when a team of researchers at University of York examined the performance of the feature, they found that it failed to recognise genuine owner of the phone. Dr. David Robertson of the Department of Psychology’s FaceVar lab from the University of York led a research team to find out a solution to this problem. They found that, instead of a single target image, if the system used a combination of different pictures of the user, the smartphone's face recognition is significantly improved.
The team published their research work in the journal PLOS ONE and described how the face recognition systems in our gadgets can be improved to a great extent if users stored an ‘average’ of their own photos – formed by morphing together several different photos. The concept behind this is that the automatic face recognition systems benefit from incorporating the advantages of familiarity. In their experiments, they found that users could unlock their phones more reliably when the device stored an average of the user’s face than when they stored a single image. Not only did this result in consistency across a wide variety of everyday viewing in various lighting conditions, but it also did not affect the rejection of imposter faces.
Smartphone-face-recognition-improved-university-york-research. Left: In a normal ‘face-unlock’ system, smartphone stores a single image of the owner. Right: Owner’s face ‘average’ – an image derived from many photos of a person – being encoded into the system. When it comes to recognising faces in a computational system, it remains a significant challenge for the cognitive sciences. Humans have been recognising faces using a variety of factors such as eye gaze, facial expression and attractiveness. Not many processes are available for processing the person’s identity. Depending upon the camera's specifications, lighting of the area, age, pose etc., a person's face varies considerably and therefore it is possible that two images of the same person could be less similar than two images of different people.
This where the proposition from York researchers comes into picture. They want to tackle this problem of varying face structure of the same person by storing many different images of the same person in memory and then using an 'average' of those photos to be used when recognisng it for letting access to a smartphone or tablet. What are your thoughts on the proposed system for improving face recognition? Have you tried our the face unlock feature available in Samsung Galaxy Android smartphones?
Pen drives or flash drives are the best way to carry huge amount of data from one place to another. Pen drives offer a cheap and reliable way to store data. They are reliable because unlike other storage mediums, they don’t have moving parts. Pen drives stores data in magnetic form and that’s why they are re writable in nature. But despite of having so many advantages of using pen drives, there are some disadvantages too. These disadvantages are nothing but only some common pen drive problems that most of us face regularly.
So today I am listing 6 common pen drive problems and their solutions.
1) Generic Volume Can’t Be Stopped Right Now: This is a common pen drive problem which occurs on windows operating system when we try to remove pen drive by clicking on safely remove hardware option. If you are getting this problem with your pen drive and want to fix it by following some easy tips, then must read this article: How to fix Generic Volume Cannot Be Stopped Right Now Pendrive Problem.
2) Remove Write protection From Pen drive: This is another common pen drive problem which comes when we want to delete the data from pen drive. You can remove write protection of a pen drive from reading this article: How to Remove Write Protection from Pen drive.
3) Pen drive is Detected but Not Showing in My Computer: Sometimes when we plug-in a pen drive to our computer, the system instantly detects it but doesn’t show it in My Computer. This happens due to disk management. In case if you want to remove this problem, Read this article: How to Fix Pen drive is detected But not showing in My Computer Problem.
4) Problem In formatting Pen drive: Sometimes when we try to format our pen drive, a pop up box appears which says “Can’t format the drive”. There are many ways to solve this pen drive problem, In case if you are facing the same problem with your pen drive, then read this article to solve it: Fix Can’t Formatthe drive pen drive problem.
5) Please Insert a Disk into Drive Pen drive Problem: This is a very common pen drive problem and comes when we insert our pen drive in our PC and try to access it via my computer. Due to this problem, Computer shows us a message which says “Please insert a Disk into drive”, if you want to solve this pen drive problem then read this article: How to fix Please insert a Disk into Drive Pen drive Problem.
6) USB Device Not Recognized or Malfunctioned: This problem comes when we plug in a pen drive to our computer, The computer displays a message in tray, which says “One of the USB device attached to your computer has malfunction”, You can fix USB Device Malfunctioned problem by following this article: How to fix USB Device has Malfunctioned Pen drive Problems.
If you are facing another pen drive problem, then you can share it in comment box below. I would feel glad to fix your pen drive problem.
Most of the people face “Please insert a disk into drive windows error” with external storage devices like pen drives and memory cards. Some people may also face this error with external HDD or Flash drives. No matter whatever is the device, the solution is not easy. You may get thousands of tools online which claims to fix please insert a disk into drive windows error, but most of them will not work. Before writing this tutorial, I tried hundreds of offline and online tools, but only 2 or 3 of them worked to solve the error.
So if you are looking for a solution of Please insert a disk into drive problem, then here are two methods to fix this error.
Method 1:
Download and install HP USB Disk Format Tool from this link. And then try to format your external storage device like pen drive, flash drive or external HDD with it. Most of the times, the tools easily fix please insert a disk into drive problem, But in case if it didn't work for you, then try the 2nd method.
Method 2:
This method will only work with transcend pen drives, If you are facing "please insert a disk into drive error" with your transcend pen drive, Then only this method will work for you.
Download and install Jet Flash online recovery tool from this link.
And then, format your pen drive with Jet Flash, if you face any problem during formatting. Then navigate to the bottom of downloading page, You will get a step by step tutorial to format Pen drives using Jet Flash.
I have fixed 2-3 pen drives with above methods, If both the above methods are not working for you. Then most probably your pen drive is facing a serious hardware problem. And you need to replace it as soon as possible.
Any kind of comments or queries will be appreciated.
This is a common pen drive problem which happens with new pen drives. You may also face same problem with other external devices like flash drives, Memory cards or external HDD. Due to this problem, whenever we plug in any external device to our computer, it gets detected easily but it doesn’t start to appear in My computer. This problem can be easily fixed by following some easy steps.
So incase if you are also facing a problem in which your pen drive is detected but not showing in my computer, then follow these simple 6 steps to solve this problem.
1) Click on Start button and then open run prompt.
2) Type compmgmt.msc, in run prompt and press enter. A computer management window will open.
3) Now Select "Disk Management" from Left hand menu, Disk management options will appear at right side of pane.
4) In disk management options, you will see some drives including your pen drive or external HDD. Now right click on your pen drive and select “Change Drive letter and paths” from the right click menu. A small window will pop-up.
5) Now click on “Change” to assign a new drive letter to your pen drive. One thing to notice here is always assign the name which is not already being used by any other drive.
6) Once done, pen drive will start appearing in my computer. If not, then reboot your computer.
What you think on this article, Please leave your valuable comments in comment box below.
Most of the times, Whenever we try to format a pen drive or other removable storage devices like memory cards, flash drives, or external HDD. We get an error like “Can’t format the drive, quit any disk utilities or other programs that are using this drive, and then try formatting again”. There may be two reasons for this problem, either your pen drive is hardware faulty or your pen drive is infected from viruses. In case if its, hardware faulty then there is no way to fix it, until and unless it’s in warranty period. If it’s due to virus infection, then you can fix the unable to format or can’t format the drive problem easily.
There are 3 ways to solve windows can’t format this drive error, you can follow any of the given ways to fix your external storage device unable to format problem.
Method 1: To Fix Unable to Format Pen drive Problem
1) Plug in pen drive into your computer and click on start button.
2) Open run prompt and type CMD and press enter. It will open MS DOS Command Prompt.
3) In Dos Prompt, Type “Format X:/FAT32”, without inverted commas and press enter. Don’t forget to replace X with your pen drive or External HDD drive letter.
4) Once done, your pen drive will start formatting.
Most of the times above method works, In case if it’s not working for you. Then follow next Method
Method 2: To Fix Unable to Format Pen drive Problem
1) Plug in your pen drive into computer, and click on start button.
2) Now, Click on Run prompt and then type “compmgmt.msc”, without inverted commas in run prompt and press enter. It will open a computer management window.
3) Click on Disk management from right pane, A Disk management options pane will open on right side.
4) Right click on your pen drive and select format.
it will format your pen drive suffering with cannot format the drive problem, In case If both the above methods are not working for you, then try the 3rd one. It will work for sure.
Method 3: To Fix Unable to Format Pen drive Problem
1) Plug in your pen drive into your computer.
2) Insert windows installation disk and reboot your computer.
3) Enter any key and proceed with the installation, at a particular point of time, It will give you a option like “Format Your PC”. Press enter key and proceed with it.
4) After that, Windows will detect all your hard disk partitions, pen drive will also appear on screen.
5) Now, Select Pen drive and then press “Delete” key to format your pen drive.
Almost each and every time, the above methods will format your pen drive, which is suffering from unable to format or cannot format the drive error. If none of the above methods are working for you, then most probably your pen drive is hardware faulty.
What you think on this article, any kind of queries will be appreciated
Pen drive write protection problem is a very common kind of external storage device problem. Most of the times whenever we want to delete some data from pen drive or another external storage medium like memory cards or External HDD, then a pop-up box appears which shows a message like “The disk is write protected, remove write protection or use another disk”. Removing write protection from pen drive is a hard job, Even we can’t format a write protected external drive. If we try to format a write protected drive then also we will get a message that “The disk is write protected”
If you are also facing write protection problem with your pen drive and want to fix it without formatting, Then here are some steps to fix or remove write protection from pen drive.
How to remove write protection from Pen drive:
1) Insert your pen drive into your computer, click on start menu, then open run prompt.
2) Type Regedit, in run prompt and press enter. This will open registry editor on your computer.
3) Now in registry editor, Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies
4) once done, Double click on the key "WriteProtect" in the right pane and set the value of “Value Data” section to 0. And then press ok.
Remove Write Protection
5) Now exit registry editor and restart your computer.
You have successfully removed the write protection from pen drive. Any queries or comments regarding this article, would be appreciated.
Generic volume can’t be stopped right now is a common windows problem and comes when we try to remove our pen drive or other removable device by using “Safely remove hardware option” that exists at the tray. It is highly recommended that whenever you try to remove any removable storage device, use “safely remove hardware” option. Because if you do so, then windows will close all the read-write operations on the storage device so that the drive can be remove without malfunctioning. But due to “Generic volume can’t be stopped right now problem”, we get an error whenever we
try to select safely remove hardware at the time of removing a storage device like pen drive. So in order to prevent your removable device from malfunctioning, solving “Generic Volume can’t be stopped right now” problem is must.
So here are the steps to fix Generic volume can’t be stopped right now error in windows:
1) Download software named unlocker from here. Unlocker is a handy utility which can be used to unlock the file handles of your removable storage devices, which are used by other applications.
2) Install unlocker.
3) open my computer and right click on the pen drive and select unlocker from right click menu.fix Generic Volume Can’t Be Stopped Right Now Pen drive
4) A small pop window will appear which will show all the busy file handles of file being used on your pen drive.
5) Finally, Click on “unlock all” and then try to remove your pen drive using safely remove hardware option.Generic Volume Can’t Be Stopped Right Now
Now, your computer will not show you “Generic volume can’t be stopped right now error” message while removing pen drive using “safely remove hardware” option.
UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.
UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.
Types of UNIX
There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.
Here in the School, we use Solaris on our servers and workstations, and Fedora Linux on the servers and desktop PCs.
The UNIX operating system
The UNIX operating system is made up of three parts; the kernel, the shell and the programs.
The kernel
The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls.
As an illustration of the way that the shell and the kernel work together, suppose a user types rm myfile (which has the effect of removing the filemyfile). The shell searches the filestore for the file containing the program rm, and then requests the kernel, through system calls, to execute the program rm on myfile. When the process rm myfile has finished running, the shell then returns the UNIX prompt % to the user, indicating that it is waiting for further commands.
The shell
The shell acts as an interface between the user and the kernel. When a user logs in, the login program checks the username and password, and then starts another program called the shell. The shell is a command line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The commands are themselves programs: when they terminate, the shell gives the user another prompt (% on our systems).
The adept user can customise his/her own shell, and users can use different shells on the same machine. Staff and students in the school have thetcsh shell by default.
The tcsh shell has certain features to help the user inputting commands.
Filename Completion - By typing part of the name of a command, filename or directory and pressing the [Tab] key, the tcsh shell will complete the rest of the name automatically. If the shell finds more than one name beginning with those letters you have typed, it will beep, prompting you to type a few more letters before pressing the tab key again.
History - The shell keeps a list of the commands you have typed in. If you need to repeat a command, use the cursor keys to scroll up and down the list or type history for a list of previous commands.
Files and processes
Everything in UNIX is either a file or a process.
A process is an executing program identified by a unique PID (process identifier).
A file is a collection of data. They are created by users using text editors, running compilers etc.
Examples of files:
a document (report, essay etc.)
the text of a program written in some high-level programming language
instructions comprehensible directly to the machine and incomprehensible to a casual user, for example, a collection of binary digits (an executable or binary file);
a directory, containing information about its contents, which may be a mixture of other directories (subdirectories) and ordinary files.
The Directory Structure
All the files are grouped together in the directory structure. The file-system is arranged in a hierarchical structure, like an inverted tree. The top of the hierarchy is traditionally called root (written as a slash / )
In the diagram above, we see that the home directory of the undergraduate student "ee51vn" contains two sub-directories (docs and pics) and a file called report.doc.
The full path to the file report.doc is "/home/its/ug1/ee51vn/report.doc"
Starting an UNIX terminal
To open an UNIX terminal window, click on the "Terminal" icon from Applications/Accessories menus.
An UNIX Terminal window will then appear with a % prompt, waiting for you to start entering commands.