Monday 19 November 2012

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Wednesday 31 October 2012

Post # 275

Q.29)Tell some of applications of buffer? (asked in verilog Interview)

Post # 274

A.28)Tie one of xor gates input to 1 it will act as inverter & Tie one of xor gates input to 0 it will act as buffer

Post # 273

Q.28)Given only two xor gates one must function as buffer and another as inverter?

Post # 272

at the end of metastable state,the flip-flop settles down to either '1' or '0'.This whole process(see last 2 msgs)is known as metastability.

Post # 271

(Contd…)this unpredictable state is known as metastable state (quasi stable state)

Post # 270

Whenever there are setup and hold time violations in any flip-flop, it enters a state where its output is unpredictable(Contd…)

Post # 269

 amnt of time after the clock edge that same i/p signal has to be held B4 changing it to make sure it is sensed properly at the clock edge.

Post # 268

Q.27)what is hold time?

Post # 267

is the amount of time before the clock edge that the input signal needs to be stable to guarantee it is accepted properly on the clock edge.

Post # 266

Q.26)what is setup time ?

Post # 265

A.25)To avoid metastable state, a series of FFs is used (normally 2 or 3) which will remove the intermediate states.

Post # 264

Q.25)How to avoid metastability?

Post # 263

A.24)metastability will happen if the O/P cap is not allowed to charge/discharge fully to the required logical levels.

Friday 26 October 2012

Post # 261

Q.24)When/why metastability will occur?

Post # 260

Q.23)What is metastability?  --- A.23)Metastable state: An un-known state in between the two logical known states.

Post # 259

A.22)If the source&drain also connected properly it acts as a buffer.But suppose I/P is logic 1,O/P will be degraded 1 Similarly degraded 0.

Post # 258

Q.22)All of us know how an inverter works.What happens when the PMOS and NMOS are interchanged with one another in an inverter?

Post # 257

A.21)B'coz,In Transmission Gate, PMOS and NMOS aid each other rather competing with each other.

Post # 256

Q.21)Why PMOS and NMOS are sized equally in a Transmission Gates?(you can check all the past posts at: jigarforelectronics.blogspot.in)

Post # 255

…If the sizes of PMOS&NMOS are same,then PMOS takes long time to charge up the output node,to nulify this PMOS size kept larger than NMOS.

Post # 254

... In CMOS technology, NMOS helps in pulling down the output to ground & PMOS helps in pulling up the output to Vdd.

Post # 253

A.20)In PMOS the carriers are holes whose mobility is less[aprrox half]than the electrons,the carriers in NMOS.i.e.PMOS is slower than NMOS.

Post # 252

Q.20)In CMOS technology, IN DIGITAL DESIGN, why do we design the size of pmos to be higher than the nmos?(verilog interview Que.)

Tuesday 23 October 2012

Post # 251

A.19)The main difference between latch and FF is that latches are level sensitive while FF are edge sensitive.

Post # 250

Q.19)What is difference between latch and flipflop?

Post # 249

(…Contd)This is because the current in BJT is exponentially dependent on input where as in MOSFET it is square law.

Post # 248

A.18)BJT has higher gain because it has higher transconductance.This is because (Contd…)

Post # 247

Q.18)Which transistor has higher gain. BJT or MOS and why?

Post # 246

A.17)BJT is a current controlled device and MOSFET is a voltage controlled device.

Post # 245

Q.17)What is the fundamental difference between a MOSFET and BJT ?

Post # 244

A.16)Because it can not drive the output load straight away, so we gradually increase the size to get an optimized performance.

Post # 243

Q.16)Why do we gradually increase the size of inverters in buffer design? Why not give the output of a circuit to one large inverter?

Post # 242

To New Members: These are E_K's Interview Questionnaire Weeks...(For Final Year B.E./B.Tech) Students.
Thanks to all for Joining

Post # 241

...Those value of Resistors are typical values, For specific application it can be any value.In mobile phones it's about of mega ohm range!

Sunday 21 October 2012

Post # 238

(….Contd.)particularly in TTL, any floating input is considered as Logic 1. But it’s never a good idea to leave the input pins unconnected.

Post # 239

Q.15) What should be the value of Pull up/Pull Down Resistors ???

Saturday 20 October 2012

Post # 240

A.15)There are no specific values for such pull-ups or pull-downs; they could be anywhere between 1K and 47K.

Post # 237

A.14) The input isn’t at zero volts but its “floating”.In electronics, an unconnected input pin is termed as floating.(Contd...)

Post # 236

Q.14) " we haven’t connected anything to the input Pin "--- What does it Mean?

Post # 235

JTAG - Port :Joint Test Action Group, A JTAG interface is a special four/five-pin interface added to a chip.

Post # 234

LQFP - LowProfile Quad Flat Package

Friday 19 October 2012

Post # 233

Q.13)Hard disk time for R/W head to move to correct sector is known as ______???---- A.13) Latency Time

Wednesday 10 October 2012

Post # 232

A.12) Elimination of waste by purchasing manufacturing exactly when needed.

Post # 231

Q.12) Explain Just In Time Concept ?

Post # 230

Q.11) Where the memory be get allocated to variables declared in a program? --  A.11) allocated on stack.

Post # 229

A.10) Buffering : the process of temporarily storing the data to allow for small variation in device speeds.

Post # 228

Q.10) What do you mean by the term Buffering ?

Post # 227

Q.9) In communication what does mean by Line of Sight ?  A.9) Tx & Rx should be visible to each other.

Monday 8 October 2012

Post # 226

Q.8)Give the expression for CMOS switching power dissipation?    A.8) CV^2

Post # 225

A.7)Power dissipation=CV^2f ,from this minimize the load capacitance, dc voltage and the operating frequency to minimise power consumption.

Post # 224

Q.7)For CMOS logic, give the various techniques you know to minimize power consumption?

Post # 223

….(contd) to compensate this we have to increase the die size which is not practical.

Post # 222

A.6)The delay can be reduced by increasing the power supply but if we do so the heating effect comes…(contd.)

Friday 5 October 2012

Post # 218


Q.6) What are the limitations in increasing the power supply to reduce delay?

Wednesday 3 October 2012

Post # 216

Q.5)What happens to delay if we include a resistance at the output of a CMOS circuit?

Post # 215

A.4) delay increases. (Any suggestion will be appreciated at jigarforelectronics.blogspot.in)

Post # 214

Q.4)What happens to delay if you increase load capacitance?[This is Interview Questionnaire week for ECE final year student].

Tuesday 2 October 2012

Post # 213

A.3)In order to drive the desired load capacitance we have to increase the size (width) of the inverters to get an optimized performance.

Post # 212

Q.3)Explain sizing of the inverter?(You can have all older posts of E_K from jigarforelectronics.blogspot.in) Thanks for joining.

Post # 211

A.2)The minimum amount of noise that can be allowed on the input stage for which the output will not be effected.

Post # 210


Q.2)What is Noise Margin? Explain the procedure to determine Noise Margin.

Monday 1 October 2012

Post # 209

A.1)because at the transistor level the mobility of electrons is normally 3times that of holes compared to NOR&thus the NAND is faster gate.

Post # 208

Q.1) Why is NAND gate preferred over NOR gate for fabrication??? (Asked in CMOS/Verilog interview)

Sunday 30 September 2012

Post # 207

E_K is going to start : Interview Questionnaire weeks for ECE final year students as this is the time of campus interview for them. Enjoy

Post # 206

PID controller : proportional–integral–derivative controller is the most commonly used feedback controller.

Post # 205

MOSFET as switch:U need  Body diode betwn the drain(to cathode)& the source(to anode),making it able to block current in only 1 direction.

Saturday 29 September 2012

Post # 204

Standard 555ICs create a significant glitch on the supply when their O/P changes state.Solution:100uF capacitor-across +Vs & 0V,near 555IC.

Friday 28 September 2012

Post # 203

In general, PWM wave form can be generated by comparing DC input voltage signal with fixed Triangular wave form.

Post # 202

With IAP(In Application Programming)you can only program the memory sections of the controller.Program will keep executing while updating.

Thursday 27 September 2012

Post # 202

With ISP (In system Programming) the entire controller can be erased or programmed. program couldn't get executed while programming.

Wednesday 26 September 2012

Post # 201

Silicon Carbide Diode:Ultra low power loss, Ultra fast switching Behaviour, No tempearature influence on switching, Very Expensive

Post # 200

Bootloader can also be known as a source code program.

Post # 199

Bootloader is a piece of code that runs before any operating system is running in Embedded systems.

Tuesday 25 September 2012

Post # 198

(contd.)…For example, a pad size of 30 mils and a drill size of 18 mils is commonly referred to as an 18C30 via (the C means circular).

Post # 197

In PCB Designing Via size is defined as a pad size and a drill size….(contd.)

Thursday 20 September 2012

Post # 196

Double-sided boards or multi-layer boards use plated-through holes, called vias, to connect traces on different layers of the PCB.

Post # 195

"mil" is a  popular unit in PCB Fabrication (for width of trace), A mil is 1/1000th of an inch.

Post # 194

The decoupling capacitor: The word “decoupling” really means “noise-absorbing”.purpose is to absorb noise generated by active device.

Post # 193

what is Netlist in softwares : netlist is usually an ASCII (text) document defining the connections shown in your schematic.

Wednesday 19 September 2012

Post # 192

Now onwards you can also have all the post of E_K at jigarforelectronics.blogspot.in--any suggestion on blog from you will be appreciated

Embedded History V

During the 1990s, microcontrollers with electrically erasable and programmable ROM (EEPROM) Memories became available.

Embedded History IV

ARM was developed/Invented at Acron Computers ltd of Cambridge, England between 1983 and 1985.

Tuesday 18 September 2012

Embedded History III

In 1976, 8048 was one of Intel's first Microcontrollers & was used as a processor in IBM PC keyboard. 8051 invented in 1980 by intel.

Embedded History II

In 1971, the first microcontroller was invented by Texas Instruments; Gary Boone and MichaelCochran created the TMS 1000,which was a 4-bit microcontroller with built-in ROM & RAM.

Embedded History I

In November, 1971, a company called Intel publicly introduced the world's first single chip microprocessor, the Intel 4004.