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1.What are the various registers in 8085? Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085 . 2.What is Stack Pointer Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack 3.What is Program counter? Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction. 4.Which Stack is used in 8085? LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first. 5.What is meant by a bus? A bus is a group of conducting lines that carriers data, address, & control signals. 6.What is Tri-state logic? Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line. 7.Give an example of one address microprocessor? 8085 is a one address microprocessor. 8.In what way interrupts are classified in 8085? In 8085 the interrupts are classified as Hardware and Software

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Page 1: fi.ge.pgstatic.netfi.ge.pgstatic.net/attachments/34342_d69a525856cc4f25…  · Web view2. What. are the various interrupts in 8086?? Maskable. interrupts, Non-Maskable. interrupts

1.What are the various registers in 8085?

Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085 .

2.What is Stack Pointer

Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack

3.What is Program counter?

Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.

4.Which Stack is used in 8085?

LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.

5.What is meant by a bus?

A bus is a group of conducting lines that carriers data, address, & control signals.

6.What is Tri-state logic?

Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.

7.Give an example of one address microprocessor?

8085 is a one address microprocessor.

8.In what way interrupts are classified in 8085?

In 8085 the interrupts are classified as Hardware and Software interrupts.

9.examples of Software interrupts?

RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.

10.EXAMPLES of Hardware interrupts?

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TRAP, RST7.5, RST6.5, RST5.5, INTR.

11.Which interrupt has the highest priority?

TRAP has the highest priority.

12.Name 5 different addressing modes?

Immediate, Direct, Register, Register indirect, Implied addressing modes.

13.How many interrupts are there in 8085?

There are 12 interrupts in 8085.

14.What is clock frequency for 8085?

3 MHz is the maximum clock frequency for 8085.

15.In 8085 which is called as High order / Low order Register?

Flag is called as Low order register & Accumulator is called as High order Register.

16.Why crystal is a preferred clock source?

Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.

17.What does Quality factor mean?

The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.

1.What are the flags in 8086?

Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.

2.What are the various interrupts in 8086??

Maskable interrupts, Non-Maskable interrupts

3.What is meant by Maskable interrupts?

An interrupt that can be turned off by the programmer is known as Maskable interrupt.

4.Which interrupts are generally used for critical events??

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Non-Maskable interrupts are used in critical events Such as Power failure, Emergency, Shut off etc.

5.What is the Maximum clock frequency in 8086?

5 Mhz is the Maximum clock frequency in 8086.

6.What are the various segment registers in 8086?

Code, Data, Stack, Extra

7.Which Stack is used in 8086?

FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.

Q1)Why a MOSFET is preferred over a transistor?A)A MOSFET is very small in size as compared to a transistor and its biasing is easier as compared to latter.

Q2)Please tell me why biasing is required in a transistor?A)Biasing is required to get the load line and the operating point of a transistor. Moreover different regions are achieved through different biasing types.

Q3)How different regions are got and what are those regions? Explain taking a Common Base connection.A)Well the transistor can be biased in 3 different types to get three different regions-Active region, Saturation Region, Cut-off RegionActive Region-:Emitter is forward biased and collector is reverse biasedCut-off Region-:Both emitter and collector are reverse biased

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Saturation region: Both emitter and collector are forward biased

Q4)What is a tunnel diode ?A)Tunnel diode was invented by Esaki and its different from the normal diode in terms of the doping concentration as in 1part of doping is present in 10^3 atoms whereas in normal diode it is 1 part in 10^8 atoms. It is basically used for very fast switching response.

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1)what is 555 and why is it named so555 Timer is used to produce accurate and stable time delays ranging from microseconds to hours.inside the 555 timer, there are 3 resistors used in seriesall the 3 resistors used are same and are 5k ohm resistors..so its called 555 timer..

2)Give Shannon's source coding and channel coding theoremSource coding theorem is stated as follows:"Given a discrete memory less source of entropy H(p), the average code-word length L for any source encoding is bounded as L >= H(p)"This is basically used for Data Compression using different codes but following this rule.Channel coding theorem says "Let a discrete memory less source with an alphabet p have entropy H(p) and produce symbols once every Ts seconds. "Let a memory less channel have capacity C and be used once every Tc seconds. Then if H(p)/Ts <= C/Tc there exists a coding scheme for which the source output can be transmitted over the channel and reconstructed with very small error."This is basically used for Error Detection.

3)what is Hoffman codingHoffman code is a source code whose average word length approaches the fundamental limit set by the entropy of a discrete memory less source. It is optimum in the sense that it follows Source coding very closely

4)Design AND/OR/NOT using transistors..Refer books

5)What is Grey coding, XS-3 coding, K-Map?

6)Why are nand gates and NOR gates called Universal gates.....Becoz using these 2 gates any other type of gates can be made

7)What is the Sampling theorem?A continuous time signal may be completely represented in its samples and recovered back if sampling frequency is greater than equal to twice the maximum frequency present in the signalFs >= 2Fm

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What is Convolution theoremTime convolution theoremConvolution in time domain = Multiplication in Frequency domainx1(t) * x2(t) <---> X1(w) x X2(w) --

Frequency Convolution theoremConvolution in frequency domain = 2pi x Multiplication in time domainX1(w) * X2(w) <---> 2pi x x1(t) x x2(t)

9)What are FIR and IIR filtersFinite impulse response and infinite impulse response filtersfinite impulse response settles to zero in a finite number of sample intervals. This is in contrast to infinite impulse response (IIR) filters, which have internal feedback and may continue to respond indefinitely FIR filters are always stable but IIR may or may not be stable

10)Why is a common collector called an emitter follower..?In this configuration the voltage gain is equal to unity and hence a change in base voltage appears as an equal change across the load at the emitter. Thus the emitter follows the input signal. The most common use of this circuit is to use as a buffer stage which functions as resistance transformation from high to low resistance.

11) What is DTMFDual-tone multi-frequency signaling (DTMF) is used for telecommunication signaling over analog telephone lines in the voice-frequency band between telephone handsets and other communications devices and the switching center.

12) what are The venin and Norton's theorems, Maximum power transfer theorem?Sometimes we need to calculate current or voltage in a particular branch of a circuit. In that case we needn't calculate for all branches..so techniques like The venin and Norton are used.In both theorems we replace the 2-terminal linear device which may contain voltage source, current source both independent and dependent with the following orientation:If they are replaced with a resistor in series with a Voltage source then its The venin and if it is replaced with a resistor in parallel with a Current source then its Norton.Maximum Power transfer theorem is basically a linear device when connected to its The venin equivalent it receives Maximum power .-----------------------------------------------------------------------------------------1.what is the difference between SCR and diode rectifier?ans: diode is a 2 terminal device, in scr gate controls the rectifing.SCR is used in High frequency applications but diode is low frequency devices, SCR can be in high temperatures but not diode.

3.Distinguish between Angle modulation and Amplitude modulation.ans: In amplitude Modulation as the amplitude of given signal varies, the

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amplitude of carrier signal also varies in the same way. In angle modulation, the frequency or phase may vary according to the amplitude of given signal

4.What is Biasing?ans: biasing is a process of connecting dc voltage to a device by which we can select the operating point of the device. by biasing actually we select the operating point of the device.

5.What do you mean by ASCII, EBCDIC?ans:ASCII (American Standard Code for Information Interchange), is a character encoding based on the English alphabet.

EBCDIC (Extended Binary Coded Decimal Interchange Code) is an 8-bit character encoding used on IBM mainframe operating systems

6. What is Race-around problem? How can you rectify it?ans: A condition in logic network in which the difference in propagation times through two or more signal paths in the network can produce an erroneous output. in jk flip flop race around problem will occur when both the inputs are high. it can be prevented by using master slave jk flip flop

7.What is the basic difference between Latches and Flip flops?ans: latch works without clock signal, but works with a control signal and it is level triggered device. Whereas flip flop is a 1 bit storage element and works with a clock signal. its a edge triggered device. normally latches are avoided and flip flops are preferred.

8. what is Barkhausen Criterion?ans:1./AB/=1,i.e. the magnitude of loop gain must be unity2.the total phase shift around the closed loop is zero or 360 degrees.

1. What is meant by D-FF? D Flip Flop (or did you mean to ask its working?)

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2. What is the basic difference between Latches and Flip flops? (Latches do not store information, here, a bit)

3. What is a multiplexer?4. How can you convert an SR Flip-flop to a JK Flip-flop?5. How can you convert an JK Flip-flop to a D Flip-flop?6. What is Race-around problem? How can you rectify it?7. Which semiconductor device is used as a voltage regulator and why?

(zener diode in reverse bias, why because it allows for a large variation in current for a negligible variation in voltage)

8. What do you mean by an ideal voltage source? (Sources infinite current to any load without any change in o/p voltage)

9. What do you mean by zener breakdown and avalanche breakdown?10. What are the different types of filters? (low pass, high pass, band

pass, band stop, resonant)11. What is the need of filtering ideal response of filters and actual

response of filters?12. What is sampling theorem? (minimum 2 samples per time

period? not too sure of this)13. What is impulse response?14. Explain the advantages and disadvantages of FIR filters

compared to IIR counterparts.15. What is CMRR? Explain briefly. (explained by someone a few

posts above)16. What do you mean by half-duplex and full-duplex

communication? Explain briefly. (half duplex - both sender & receiver can communicate with each other, but not simultaneously...full duplex - same but simultaneous communication possible)

17. Which range of signals are used for terrestrial transmission?18. What is the need for modulation? (transmitting over a distance,

encryption?)19. Which type of modulation is used in TV transmission?20. Why we use vestigial side band (VSB-C3F) transmission for

picture?21. When transmitting digital signals is it necessary to transmit some

harmonics in addition to fundamental frequency?22. For asynchronous transmission, is it necessary to supply some

synchronizing pulses additionally or to supply or to supply start and stop bit?

23. BPFSK is more efficient than BFSK in presence of noise. Why?24. What is meant by pre-emphasis and de-emphasis?25. What do you mean by 3 dB cutoff frequency? Why is it 3 dB, not

1 dB? (3dB is the half power value)26. What do you mean by ASCII, EBCDIC?

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The basic difference in layman's terms is:

While both provide backup power during mains outage, with the UPS the switch is instantaneous whereas with the Inverter there is a gap of a second or two. This gap is OK for household gadgets such as lights, fans, fridge, etc. but not OK for computers.

In technical terms:

UPS: The mains power comes to the UPS. The AC is converted to DC and this DC is constantly charging the battery. The output of the battery is fed to the Sine wave inverter and it converts DC to AC and this feeds the equipment. Since power out is always drawn from the battery, there is no time lag when mains switches off; it just stops the battery from being charged and the UPS continues to supply power till the battery runs out.

Inverter: The mains power comes to the Inverter. This is directly sent to the output but the AC is also converted to DC and this DC is constantly charging the battery. A sensor and relay mechanism checks whether the mains is ON or OFF. When the main switches OFF, the relay actuator triggers to switch from mains to inverter. Rest is same like the UPS. Because of this sensor and relay, there is a gap between triggering.

UPS involves more costly circuitry and is therefore more expensive to make and sell.