Power Electronics MCQ serires 1

Power Electronics MCQ series
🔥#1 Top 20 MCQ Of  Power Electronics | LMRC | UPPCL-JE | All Competitive Exam MCQ | Important MCQ |
Power electronics MCQ Series – 1

Top 20 questions of power electronics. For explanation of each answer you can watch my video

Question 1: A thyristor is basically

  • PNPN device
  • A combination of diac and triac
  • A set of SCRs
  • A set of SCR, diac and a triac

Answer: PNPN device

Question 2: A silicon controlled rectifier (SCR) is a

  • Unijunction device
  • Device with three junction
  • Device with four junction
  • None of the above

Answer: Device with three junction

Question 3: A thyristor equivalent of a thyratron tube is a

  • Diac
  • Triac
  • Silicon controlled rectifier
  • None of the above

Answer: Silicon controlled rectifier

Question 4: An SCR is made up of silicon because

  • Silicon has large leakage current than germanium
  • Silicon has small leakage current than germanium
  • Silicon has small leakage voltage than germanium
  • Silicon has large leakage voltage than germanium

Answer: Silicon has small leakage current than germanium

Question 5: An SCR is considered to be a semi controlled device because

  • It can be turned OFF but not ON with a gate pulse.
  • It conducts only during one half cycle of an alternating current wave.
  • It can be turned ON but not OFF with a gate pulse.
  • It can be turned ON only during one half cycle of an AC.

Answer: It can be turned ON but not OFF with a gate pulse.

Question 6: Which statement is true for latching current ?

  • It is related to turn off process of the device.
  • It is related to conduction process of device.
  • It is related to turn on process of the device.
  • Both C and D.

Answer: It is related to turn on process of the device.

Question 7: If holding current of a thyristor is 2 mA then latching current should be

  • 0.01 A.
  • 0.002 A.
  • 0.009 A.
  • 0.004 A

Answer: 0.004 A

Question 8: In reverse blocking mode of a thyristor

  • junction J2 is in reverse bias and J1, J3 is in forward bias.
  • junction J3 is in forward bias and J1, J2 in reverse bias.
  • junction J1, J3 is in reverse bias and J2 is in forward bias.
  • junction J1 and J2 is in forward bias and J3 is in reverse bias.

Answer: junction J1, J3 is in reverse bias and J2 is in forward bias.

Question 9: During the commutation period in 3 phase converter, overlap time is

  • Dependent on the load current
  • Dependent on the voltage
  • Dependent on both the load current and load voltage behind the short circuit current
  • Independent on both the load current and load voltage

Answer: Dependent on both the load current and load voltage behind the short circuit current

Question 10: A UJT has ___________.

  • Two pn junctions
  • One pn junction
  • Three pn junctions
  • None of the above

Answer: One pn junction

Question 11: The UJT may be used as ___________.

  • Am amplifier
  • A sawtooth generator
  • A rectifier
  • None of the above

Answer: A sawtooth generator

Question 12: The fig. below represents a

  • Triac thyristor
  • Diac trigger
  • Diode rectifier
  • None of the above

Answer: Diac trigger

Question 13: A diac has ______________ pn junctions.

  • One
  • Two
  • Three
  • Four

Answer: Two

Question 14: What is a TRIAC?

  • Two thyristors connected in series mode
  • Two thyristors connected in parallel mode
  • Two thyristors connected in anti parallel mode
  • Two transistors connected in anti parallel mode

Answer: Two transistors connected in anti parallel mode

Question 15: For an SCR, dv/dt protection is achieved through

  • RC across SCR
  • RL in series with SCR
  • L across SCR
  • L in series with SCR

Answer: RC across SCR

Question 16: Power diode is __________

  • a three terminal semiconductor device
  • a two terminal semiconductor device
  • a four terminal semiconductor device
  • a three terminal analog device

Answer: a two terminal semiconductor device

Question 17: An ideal power diode must have

  • low forward current carrying capacity
  • large reverse breakdown voltage
  • high ohmic junction resistance
  • high reverse recovery time

Answer:

Question 18: A diode is said to be forward biased when the

  • cathode is positive with respect to the anode
  • anode is positive with respect to the cathode
  • anode is negative with respect to the anode
  • both cathode & anode are positive

Answer: anode is positive with respect to the cathode

Question 19: To make a signal diode suitable for high current & high voltage carrying applications with minimum losses, ________

  • a lightly doped n layer is grown between the two p & n layers
  • a heavily doped n layer is grown between the two p & n layers
  • a lightly doped p layer is grown between the two p & n layers
  • a heavily doped p layer is grown between the two p & n layers

Answer: a lightly doped n layer is grown between the two p & n layers

Question 20: Which one of the following statements is TRUE for an ideal power diode?

  • Reverse recovery time is non zero and reverse saturation current is zero
  • Forward voltage drop is zero and reverse saturation current is non zero
  • Forward voltage drop is non zero and reverse recovery time is zero
  • Forward voltage drop is zero and reverse recovery time is zero

Answer: Forward voltage drop is non zero and reverse recovery time is zero


FAQ

What is a thyristor ?

Thyristor is also called a silicon-controlled rectifier (SCR), it is basically a four-layer three-junction pnpn device. It has three terminals: anode, cathode, and gate.
Thyristor is basically an electronic switching device which can remain in conducting (on) and nonconducting state. However, it is a unidirectional device and can conduct only in one direction like a diode. The switching state of the device can be controlled by one of its terminals.

What is silicon controlled rectifier (SCR)?

The thyristor is also called a silicon-controlled rectifier (SCR), it is basically a four-layer three-junction pnpn device. It has three terminals: anode, cathode, and gate.
The silicon control rectifier (SCR) consists of four layers of semiconductors, which form NPNP or PNPN structures, having three P-N junctions labeled J1, J2 and J3, and three terminals.

Which thyristor is equivalent of a thyratron tube?

SCR, The thyratron is a type of gas-filled tube which is used as a high voltage electrical switch and a controlled rectifier.

Why SCR is considered to be a semi controlled device ?

During positive half cycle SCR is in forward blocking mode. By applying gate pulse the SCR can be turned ON during forward blocking mode. But SCR can not be turned OFF by applying gate pulse. It automatically turns off when anode current is below the Holding current. That is why it is called semi controlled rectifier.

What is latching current?

Latching current is the minimum required anode current to turn on SCR. Latching current is 2 or 3 times of holding current

What is holding current?

Holding current is the minimum anode current below which SCR get turn off. Holding current is 2 or 3 times less than latching current.

What is reverse blocking mode of a thyristor?

When a negative voltage is applied to the anode and a positive voltage to the cathode, the SCR is in reverse blocking mode, making J1 and J3 reverse biased and J2 forward biased.
The device behaves as two reverse-biased diodes connected in series. A small leakage current flows. This is the reverse blocking mode.

What is unijunction transistor (UJT)?

A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier.

What is power diode?

It has two terminals anode and cathode same as that of a ordinary diode. In fact, a power diode is nothing but a signal diode with a extra layer.


#1 Basic Electronics MCQ

20 Basic electronics MCQ’s

Question 1 The most commonly used semiconductor is ………

  • Germanium
  • Silicon
  • Carbon
  • Sulphur

Answer – Silicon

Question 2 The resistivity of a pure silicon is about ……………

  • 100 Ω cm
  • 6000 Ω cm
  • 3 x 105 Ω m
  • 6 x 10-8 Ω cm

Answer – 6000 Ω cm

Question 3 A semiconductor is formed by ……… bonds.

  • Covalent
  • Electrovalent
  • Co-ordinate
  • None of the above

Answer – Covalent

Question 4 A pentavalent impurity has ………. Valence electrons

  • 3
  • 5
  • 4
  • 6

Answer – 5

Question 5 A semiconductor has generally ……………… valence electrons.

  • 2
  • 3
  • 6
  • 4

Answer – 4

Question 6 A hole in a semiconductor is defined as …………….

  • A free electron
  • The incomplete part of an electron pair bond
  • A free proton
  • A free neutron

Answer – The incomplete part of an electron pair bond

Question 7 Addition of trivalent impurity to a semiconductor creates many ……..

  • Holes
  • Free electrons
  • Valence electrons
  • Bound electrons

Answer – Holes

Question 8 Addition of pentavalent impurity to a semiconductor creates many ……..

  • Free electrons
  • Holes
  • Valence electrons
  • Bound electrons

Answer – Free electrons

Question 9 In a semiconductor, current conduction is due to …

  • Only holes
  • Only free electrons
  • Holes and free electrons
  • None of the above

Answer – Holes and free electrons

Question 10 The battery connections required to forward bias a pn junction are ……

  • +ve terminal to p and –ve terminal to n
  • -ve terminal to p and +ve terminal to n
  • -ve terminal to p and –ve terminal to n
  • None of the above

Answer – +ve terminal to p and –ve terminal to n

Question 11 A forward biased pn junction diode has a resistance of the order of

  • Ω
  • None of the above

Answer – Ω

Question 12 The barrier voltage at a pn junction for germanium is about ………

  • 5 V
  • 3 V
  • Zero
  • 0.3 V

Answer – 0.3 V

Question 13 A reverse bias pn junction has …………

  • Very narrow depletion layer
  • Almost no current
  • Very low resistance
  • Large current flow

Answer – Almost no current

Question 14 A pn junction acts as a ……….

  • Controlled switch
  • Bidirectional switch
  • Unidirectional switch
  • None of the above

Answer – Unidirectional switch

Question 15 In the depletion region of a pn junction, there is a shortage of ……..

  • Acceptor ions
  • Holes and electrons
  • Donor ions
  • None of the above

Answer – Holes and electrons

Question 16 The leakage current across a pn junction is due to …

  • Minority carriers
  • Majority carriers
  • Junction capacitance
  • None of the above

Answer – Minority carriers

Question 17 When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on……

  • Junction capacitance
  • Minority carriers
  • Majority carriers
  • None of the above

Answer – Minority carriers

Question 18 With forward bias to a pn junction , the width of depletion layer ………

  • Decreases
  • Increases
  • Remains the same
  • None of the above

Answer – Decreases

Question 19 At room temperature, an intrinsic semiconductor has ……….

  • Many holes only
  • A few free electrons and holes
  • Many free electrons only
  • No holes or free electron

Answer – A few free electrons and holes

Question 20 The leakage current in a pn junction is of the order of

  • Aa
  • mA
  • kA
  • µA

Answer – µA


Topics


FAQ – Frequently ask questions

Which is most commonly used semiconductor?

Silicon, Silicon is the most used semiconductor in power electronic components like diodes, thyristors, IGBT, MOSFET transistors.

How Semiconductor form?

A semiconductor is form by covalent bond with his neighboring atoms.
In covalent bonding each valence electron is shared by two atoms

How many valence electrons in a pentavalent impurity atom?

In pentavalent impurity atom 5 valence electron in their outer most cell

How pn junction acts?

pn junction acts as a unidirectional switch

In a pn junction leakage current is due to

Minority carriers

Family Of Microcontroller

 

Before I explain about Family Of Microcontroller Let’s get start with introduction of Microcontroller

What Is Microcontroller ?

A Microcontroller is an IC (Integrated Circuit) that consist CPU, memory, I/O ports, Serial ports, Timers, Interrupts, and Clock circuits in a single chip. But it is Used for some specific applications.

So we can say that “A microcontroller is a microprocessor with integrated peripherals”. Microcontroller consists of all features that are found in microprocessors with additional built-in ROM, RAM, I/O ports, Serial ports, Timers, Interrupts, and Clock circuits. It is a programmable device mostly used in embedded systems

Family of Microcontroller

There are so many microcontroller are available in microcontroller family these are 8051, PIC, ARM, etc

8051 microcontroller

In 1981, Intel introduced an 8-bit microcontroller called the 8051 Microcontroller. It is based on Harvard architecture and it is used as an embedded system. It is fabricate using VLSI technology. There are different types of microcontrollers existing in the market now a day those are 4-bit, 8-bit, 64-bit & 128-bit

Feature Of 8051 Microcontroller

  • 4KB bytes on-chip program memory (ROM)
  • 128 bytes on-chip data memory (RAM)
  • Four register banks ( Bank 0- Bank 3)
  • 128 user defined software flags
  • 8-bit bidirectional data bus
  • 16-bit unidirectional address bus
  • 32 general purpose registers each of 8-bit
  • 2- sixteen bit Timer/Counter ( Timer 0 and Timer 1)
  • Three internal and two external Interrupts
  • 32 bidirectional I/O lines arranged as four 8-bit port ( port 0 – port 3)
  • 16-bit program counter and data pointer
  • Direct bit and byte addressability
  • 8051 may also have a number of special features such as UARTs, ADC, Op-amp, etc.
  • The other family member of 8051 microcontroller are 8052 and 8031 microcontrollers.

PIC Microcontroller

  • PIC stands for Peripheral Interface Microcontroller
  • PIC microcontroller was developed in 1993 by Microchip Technology.
  • PIC microcontrollers are the worlds smallest microcontrollers that can be programmed to carry out a huge range of tasks.
  • It is based on Harvard memory architecture.
  • It is basically RISC microcontroller.
  • These microcontrollers are very fast and easy to execute a program compared with other microcontrollers. 
  • It is controlled by software and programmed in such a way that it performs different tasks and controls a generation line.
  • PIC microcontrollers are used in different new applications such as smartphones, audio accessories, computer control systems, alarm systems, embedded systems, etc. 
  • There are many PICs available in the market ranging from PIC16F84 to PIC16F887.
  • It is programmed and simulated by a circuit-wizard software.
  • PIC microcontrollers are very popular due to their ease of programming, wide availability, easy to interfacing with other peripherals, low cost, large user base and serial programming capability (reprogramming with flash memory),  etc.
  • The main features of PIC microcontrollers are RAM, flash memory, Timers/Counters, EEPROM, I/O Ports, USART, CCP (Capture/Compare/PWM module), SSP, Comparator, ADC, PSP(parallel slave port), LCD and ICSP (In Circuit Serial Programming).
  • The 8-bit PIC microcontroller is classified into four types on the basis of internal architecture such as Base Line PIC, Mid Range PIC, Enhanced Mid Range PIC and PIC18.stands for

ARM Microcontroller

  • The ARM stands for Advanced RISC machine .
  • It was first introduced by the Acron computers organization  in 1987.
  • ARM makes 32-bit and 64-bit RISC multi-core processors.
  • The ARM microcontrollers are cost sensitive and high performance devices which are used in a wide range of application such as  industrial  instrument control systems, wireless networking and sensors and automotive system etc.
  • The ARM is a family of the microcontroller developed by the different manufacturers such as ST microelectronics, Motorola and so on. 
  • The ARM microcontroller architecture come with a few different versions such as ARMv1, ARMv2 etc and each one has its own advantage and disadvantages.
  • The ARM cortex microcontroller is an advanced microcontroller in the ARM family, which is developed by the ARMv7 architecture.

Motorola 68HC11

  • The 68HC11 (6811 or HC11 for short) is an 8-bit microcontroller (µC) family introduced by Motorola in 1984.
  • It descended from the Motorola 6800 microprocessor by way of the 6801.
  •  It is a CISC (complex instruction set computer) microcontroller.
  • The 68HC11 devices are more powerful and more expensive than the 68HC08 microcontrollers.
  • It is used in automotive applications, barcode readers, hotel card key writers, amateur robotics, and various other embedded systems. 
  • The MC68HC11A8 was the first microcontroller to include CMOS EEPROM.

AVR Microcontroller

  • AVR is another member of microcontroller family.
  • It is developed since 1996 by Atmel and acquired by Microchip Technology in 2016.
  • It is an 8-bit RISC (Reduced Instruction Set Computer) architecture microcontroller.

8051 Microcontroller MCQ # 1

Hi all, This is first part of 8051 microcontroller multiple choice questions series. In this MCQ series i have explained top 20 multiple choice questions. If you want to see more questions on 8051 microcontroller then check my next post here.

This series will help in competitive exam like UPPCL- JE, SSC JE, RSEB, RRB and all competitive exam.

Please checkout all multiple choice questions like Microcontroller, Power electronics, PLC and SCADA and 8086 microprocessor here. later I will add more questions in this series. So more update check frequently.

Question 1 Which is not the feature of 16-bit microcontroller?

  • Large program & data memory spaces
  • High speed
  • I/O Flexibility
  • Limited Control Applications

Answer : Limited Control Applications

Question 2 Which is false about microcontroller?

  • Microcontrollers are used to execute a single task within an application.
  • It consists of CPU, RAM, ROM, I/O ports.
  • Its power consumption is high because it has to control the entire system.
  • It is built with CMOS technology

Answer : Its power consumption is high because it has to control the entire system.

Question 3 At what PIN number, there is EA pin which stands for External Access input?

  • PIN 28
  • PIN 29
  • PIN 30
  • PIN 31

Answer : PIN 31

Question 4 Unlike microprocessors, microcontrollers make use of batteries because they have:

  • high power dissipation
  • low power consumption
  • low voltage consumption
  • low current consumption

Answer : low power consumption

Question 5 What is the order decided by a processor or the CPU of a controller to execute an instruction?

  • decode, fetch, execute
  • execute, fetch, decode
  • fetch, execute, decode
  • fetch, decode, execute

Answer : fetch, decode, execute

Question 6 How are the performance and the computer capability affected by increasing its internal bus width?

  • It increases and turns better
  • It decreases
  • Remains the same
  • Internal bus width doesn’t affect the performance in any way

Answer : It increases and turns better

Question 7 How many bytes of bit addressable memory is present in 8051 based microcontrollers?

  • 8 bytes
  • 32 bytes
  • 16 bytes
  • 128 bytes

Answer : 16 byte

Question 8 MOV A, @ R1 will:

  • copy R1 to the accumulator
  • copy the accumulator to R1
  • copy the contents of memory whose address is in R1 to the accumulator
  • copy the accumulator to the contents of memory whose address is in R1

Answer : copy the contents of memory whose address is in R1 to the accumulator

Question 9 How does the microcontroller communicate with the external peripherals / memory?

  • via I/O ports
  • via register arrays
  • via memory
  • all of the above

Answer : via I/O ports

Question 10 What is the file extension is used to load in a microcontroller to execute an instruction?

  • .doc
  • .c
  • .txt
  • .hex

Answer : .hex

Question 11 What is internal RAM memory of 8051 microprocessor?

  • 32 bytes
  • 64 bytes
  • 128 bytes
  • 256 bytes

Answer : 128 bytes

Question 12 When the microcontroller execute some arithmetic operations, then the flag bit of which register are affected ?

  • PSW
  • SP
  • DPTR
  • PC

Answer : PSW

Question 13 8051 microcontroller is designed by Intel in?

  • 1980
  • 1981
  • 1982
  • 1983

Answer : `1981

Question 14 Why is CHMOS technology preferred over HMOS technology for designing the devices of MCS-51 family?

  • Due to higher noise immunity
  • Due to lower power consumption
  • Due to higher speed
  • All of the above

Answer : Due to lower power consumption

Question 15 Which among the below mentioned devices of MCS-51 family does not possess two 16 -bit timers/counters?

  • 8031
  • 8052
  • 8751
  • All of the above

Answer : All of the above

Question 16 Which operations are performed by stack pointer during its incremental phase?

  • Push
  • Pop
  • Return
  • All of the above

Answer : Push

Question 17 Which of the following register usually store the output generated by ALU in several arithmetic and logical operations?

  • Special Function Register
  • Timer Register
  • Accumulator
  • Stack Pointer

Answer : Accumulator

Question 18 8051 series has how many 16 bit registers?

  • 2
  • 3
  • 1
  • 0

Answer : 2

Question 19 8051 microcontrollers are manufactured by which of the following companies?

  • Atmel
  • Philips
  • Intel
  • All of the mentioned

Answer : All of the mentioned

Question 20 Which IO Port can be used for higher address byte with addresses A8-A15?

  • PORT1
  • PORT0
  • PORT3
  • PORT2

Answer : PORT2


FAQ

What is Microcontroller?

Microcontroller is a combination of two words micro and controller, Micro means small in size and controller means a device that can control the operation of any system. So we can say that a microcontroller is a microprocessor with integrated peripherals.

What is the order decided by a processor or the CPU of a controller to execute an instruction?

First instruction is fetched from Program Memory, then fetching, instruction is decoded to generate control signals to perform the intended task. After decoding, instruction is executed and the complete intended task of that particular instruction.

How are the performance and the computer capability affected by increasing its internal bus width?

As the bus width increases, the number of bits carried by bus at a time increases as a result of which the total performance and computer capability increases.

How many bytes of bit addressable memory is present in 8051 based microcontrollers?

8051 microcontrollers have 16 bytes of bit addressable memory.

How many timers/counter 8051 microcontroller have?

8051 Microcontroller 8051 have 2 timers/counter.

When was intel design first 8051 microcontroller?

8051 microcontroller is designed by Intel in 1981. It is an 8-bit microcontroller

Why is CHMOS technology preferred over HMOS technology for designing the devices of MCS-51 family?

Micro Controllers are made by using the concept of VLSI technology. So here, CMOS based logic gates are coupled together by this technique that consumes low power.

8051 series has how many 16 bit registers?

8051 microcontroller has two 16 bit registers DPTR and PC.

8051 microcontrollers are manufactured by which of the following companies?

8051 microcontrollers are manufactured by Intel, Atmel, Philips/Signetics, Infineon, Dallas Semi/Maxim.

Which IO Port can be used for higher address byte with addresses A8-A15?

PORT2 : This port can be used for higher address byte with addresses A8-A15. When no memory is added then this port can be used as a general input/output port similar to Port 1.

Topics


#4 Top 50 PLC and SCADA MCQ

Important 50 Multiple Choice Question based on PLC and SCADA


Question 1: What is the full form of SCADA?

  • Supervisory Control and Document Acquisition
  • Supervisory Control and Data Acquisition
  • Supervisory Column and Data Assessment
  • Supervisory Column and Data Assessment

Answer: Supervisory Control and Data Acquisition

Question 2: DCS is a ______

  • Distributed Control System
  • Data Control System
  • Data Column System
  • Distributed Column System

Answer: Distributed Control System

Question 3 The control in SCADA is _____________

  • Online control
  • Direct control
  • Supervisory control
  • Automatic control

Answer: Supervisory control

Question 4 What is SCADA?

  • Software
  • Process
  • System
  • Hardware

Answer: Process

Question 5 Which of the following is not the component of a SCADA system?

  • Database server
  • I/O system
  • PLC controller
  • Sparger controller

Answer: Sparger controller

Question 6 When did the SCADA start?

  • 1980s
  • 1990s
  • 1970s
  • 1960s

Answer:1960s

Question 7 When did Windows become the world standard operating system?

  • 1980s
  • 1990s
  • 1970s
  • 1960s

Answer: 1990s

Question 8 How many levels are present in a complex SCADA system?

  • 3 – levels
  • 5 – levels
  • 4 – levels
  • 6 – levels

Answer: 4 – levels

Question 9 What is the full form of RAID

  • Redundant Array of Independent Drives
  • Redundant Array of Inexpensive Disks
  • Redundant Array of Independent Disks
  • All of the above

Answer: All of the above

Question 10 Which of the following is used for centralized network databases?

  • RAID 2
  • RAID 5
  • RAID 1
  • RAID 2

Answer: RAID 5

Question 11 Which of the following is the heart of a SCADA system?

  • PLC
  • HMI
  • Alarm task
  • I/O task

Answer: I/O task

Question 12 Which of the following is an example of the SCADA system?

  • Emerson Delta V
  • Honeywell Plant Scape
  • Yokogawa CENTUM
  • Power Studio Deluxe

Answer: Power Studio Deluxe

Question 13 What does NC stands for?

  • New Configuration
  • Normally Close
  • Normal Classes
  • Never Closing

Answer: Normally Close

Question 14 What is nominal DC voltage given to PLC?

  • +10V
  • +24V
  • +5V
  • +12V

Answer: +5V

Question 15 In which of the following is a PLC Programming tool.

  • RS Logix 500
  • RS view 32
  • Keil u vision
  • Core Vision AVR

Answer: RS Logix 500

Question 16 Among following which one is a PLC Programming Language

  • Assembly
  • Ladder Logic
  • Java
  • HTML

Answer: Ladder Logic

Question 17 In which of the following is the SCADA Software?

  • OrCAD
  • RS View32
  • Keil u vision
  • Porteous

Answer: RS View32

Question 18 Ladder logic programming consists primarily of:

  • Virtual relay contacts and coils
  • Logic gate symbols with connecting lines
  • Function blocks with connecting lines
  • Text-based code
  • Hieroglyphics

Answer: Virtual relay contacts and coils

Question 19 Examine-on instruction in PLC language is symbolically represented by what shape?

  • -] [-
  • -( )-
  • -]/[-
  • None of these

Answer: -] [-

Question 20 The symbol -(L)- represent what instruction in the PLC language?

  • OUT output unlatch instruction.
  • OTL output latch instruction
  • Examine off instruction.
  • Output energize instruction

Answer: OTL output latch instruction

Question 21 In a PLC, the scan time refers to the amount of time in which …..

  • The technician enters the program
  • Timers and counters are indexed by
  • One “rung” of ladder logic takes to complete
  • The entire program takes to execute
  • Transmitted data communications must finish

Answer: The entire program takes to execute

Question 22 The Boolean representation of this PLC program is:

  • ABC + D
  • C + (A + B)D
  • C + D(A + B)
  • ABC + BD
  • C(AB + D)

Answer: C(AB + D)

Question 23 What is the color used for NO type switches?

  • Red
  • Green
  • non of the above

Answer: non of the above

Question 24 To reset the time for a PLC what condition must be true?

  • Reset rung of TON must be true.
  • Reset rung of TON must be false.
  • RST instruction with timer address must be true.
  • RST instruction with associated timer address must be false

Answer: RST instruction with timer address must be true.

Question 25 The below rung would represent what Boolean equation?

  • X • Y = Z
  • X + Y = Z
  • X • Y’ = Z
  • None of the above.

Answer: X • Y’ = Z

Question 26 To increase the number of inputs and outputs of the PLC, one can use expansion modules.

  • True.
  • False.
  • None of the above.

Answer: True.

Question 27 Solenoids, lamps, motors are connected to:

  • Analog output.
  • Digital output.
  • Analog input.
  • Digital input

Answer: Digital output.

Question 28 The _____ is moved toward the relay electromagnet when the relay is on.

  • Armature
  • Coil
  • NO contact
  • NC contact

Answer: Armature

Question 29 In a current sinking DC input module _____

  • The current flows out of the input field device
  • Requires that a AC sources be used with mechanical switches
  • The current flows out of the input module
  • Currents can flow in either direction at the input module

Answer: The current flows out of the input field device

Question 30 AC output field devices can interface to _____

  • AC output modules
  • Relay output modules
  • Both a and b
  • Neither a or b

Answer: Both a and b

Question 31 The difference between online and offline PLC programming is . . .

  • Whether the PLC is running or stopped
  • Whether the programming PC has internet connectivity
  • The type of programming cable used
  • Where the edited program resides
  • The type of programmer used

Answer: Where the edited program resides

Question 32 In PLC programming, a retentive function is one that:

  • Defaults to the “on” state
  • Comes last in the program
  • Defaults to the “off” state
  • Cannot be edited or deleted
  • Is not reset after a power cycle

Answer: Is not reset after a power cycle

Question 33 Normally open contacts are open when:

  • When Input is not energized
  • When the input is energized
  • When input is higher than 20 volts
  • None of these

Answer: When Input is not energized

Question 34 What is the largest integer number that a PLC counter function can reach if it uses a 16 bit register?

  • 32,768
  • 65,535
  • 65,536
  • 65,537
  • 32,767

Answer: 65,535

Question 35 An NOR function implemented in ladder logic uses:

  • Normally-closed contacts in series
  • Normally-open contacts in series
  • A single normally-closed contact
  • Normally-open contacts in parallel
  • Normally-closed contacts in parallel

Answer: Normally-closed contacts in series

Question 36 Which of the following instruction enables a jump to a subroutine?

  • JMP
  • SBR
  • RET
  • None of the above

Answer: JMP

Question 37 What are the features of SCADA?

  • Control feature using a graphical representation
  • Alarm Handling
  • Security Management
  • All of the above

Answer: All of the above

Question 38 Leading SCADA providers companies are.

  • Siemens WinCC
  • Microsoft
  • TCS
  • All of the above

Answer: Siemens WinCC

Question 39 What is Scripts in SCADA?

  • Scripts are basically a form
  • Scripts are basically a function
  • Scripts are basically a facility
  • Scripts are basically a favorite

Answer: Scripts are basically a function

Question 40 What is CIMPLICITY?

  • SCADA package
  • SCADA hardware
  • SCADA software
  • SCADA handler

Answer: SCADA package

Question 41 A good application for a timed interrupt in a PLC program would be:

  • A communications function block
  • A PID function block
  • A math function block
  • A motor start/stop rung
  • A “watchdog” timer

Answer: A PID function block

Question 42 What is the full form of RTU ?

  • Remote Terminate Unit
  • Remote Terminal Unit
  • Remote Translation Unit
  • Remote Transfer Unit

Answer: Remote Terminal Unit

Question 43 What is the full form DDE?

  • Dynamic Data Exchange
  • Data Dynamic Exchange
  • Domain Data Exchange
  • Different Data Exchange

Answer: Dynamic Data Exchange

Question 44 What is the difference between SCADA and HMI.

  • Both are same
  • HMI is not related with SCADA
  • HMI can be a part of SCADA but SCADA can’t be a part of HMI.
  • SCADA is a part of HMI

Answer: HMI can be a part of SCADA but SCADA can’t be a part of HMI.

Question 45 What are the differences between PLC and SCADA?

  • PLC is a hardware part while SCADA is a software part.
  • PLC is a  software  part while SCADA is a hardware part.
  • Both are hardware unit
  • Both are software

Answer: PLC is a hardware part while SCADA is a software part.

Question 46 A PLC consists of

  • Processor Unit
  • Program Memory
  • Input/output Section
  • Display Device
  • All of the above

Answer: All of the above

Question 47 An OR function implemented in ladder logic uses:

  • Normally-closed contacts in series
  • Normally-open contacts in series
  • A single normally-closed contact
  • Normally-open contacts in parallel
  • Normally-closed contacts in parallel

Answer: Normally-open contacts in parallel

Question 48 What is the full form of NEMA ?

National Electronics Manufacturing Association
National Electrical Manufacturing Association 
National Electrotechnical Manufacturing Association 
National Electromechanical Manufacturing Association 

Answer: National Electrical Manufacturing Association 

Question 49 Which of the following is not element of SCADA:

  • SCADA Communication
  • Mono Terminal Units
  • PLCs
  • RTUs

Answer: Mono Terminal Units

Question 50 Identify the problem in this motor control PLC program:

  • Coil
  • Start contact
  • Seal-in contact
  • Stop contact
  • Power source

Answer: Seal-in contact


Difference between Microprocessor and Microcontroller

What Is Microprocessor ?

A microprocessor is an integrated circuit that consist Only CPU (Central Processing Unit). It consists of an ALU, control unit and many registers, Where ALU performs arithmetic and logical operations on the data received from an input device or memory.

Control unit controls the instructions and flow of data within the computer and, number of registers like Register B, Register C, Register D, Register E, Register H, Register L, and accumulator.

Block diagram of 8086 microprocessor

What Is Microcontroller ?

Microcontroller is a microprocessor based integrated peripherals. It contain CPU, ROM, RAM, timers, counters, I/O ports, ADC, DAC, serial communication all functional block on a single chip, which make it a complete system.

Microcontroller is dedicated to performing a particular task and execute one specific application. It is specially designed circuits for embedded applications and is widely used in automatically controlled electronic devices. In microcontroller you cannot modify the size of RAM, ROM and other components. Once a controller is designed the structure is fixed. So, the structure of the microcontroller is not flexible.

Components of Microcontroller


Some Key Difference between Microprocessor and Microcontroller

  • Microprocessor consists of only a Central Processing Unit, whereas Micro Controller contains a Memory, I/O ports, timers, counters other peripherals along with the CPU or processor.
  • Microprocessor is used in Personal Computers whereas Micro Controller is used in an embedded system.
  • Microprocessor uses an external bus to interface to RAM, ROM, and other peripherals, on the other hand, Microcontroller uses an internal controlling bus.
  • Microprocessors are based on Von Neumann model Micro controllers are based on Harvard architecture
  • Microprocessor structure is flexible. Microcontroller structure of the is not flexible means in microcontroller you cannot modify the size of RAM, ROM and other components. Once a controller is designed the structure is fixed.

Both ICs have different applications and have their own advantages and disadvantages. They can be differentiated in terms of Applications, structure, internal parameters, power consumption, and cost.

So, Let’s see the difference between the microprocessor and microcontroller in detail.


Microprocessor vs Microcontroller

MicroprocessorMicrocontroller
1) Microprocessor is the heart of Computer system. Micro Controller is the heart of an embedded system.
2) It is only a stand alone processor, so memory and I/O components need to be connected externally. Micro Controller has a processor along with internal memory and I/O components.
3) Memory and I/O has to be connected externally, so the circuit becomes large. Memory and I/O are already present, and the internal circuit is small.
4) You can’t use it in compact systems. You can use it in compact systems.
5) Cost of the entire system is high. Cost of the entire system is low.
6) Due to external components, the total power consumption is high. Therefore, it is not ideal for the devices running on stored power like batteries. As external components are low, total power consumption is less. So it can be used with devices running on stored power like batteries.
7) Most of the microprocessors do not have power saving features.Most of the microcontrollers offer power-saving mode.
8) It is mainly used in personal computers.It is used mainly in a washing machine, MP3 players, and embedded systems.
9) Microprocessor has a smaller number of registers, so more operations are memory-based.Microcontroller has more register. Hence the programs are easier to write.
10) Microprocessors are based on Von Neumann model.Micro controllers arc based on Harvard architecture.
11) It is a central processing unit (CPU) on a single silicon-based integrated chip.It is a byproduct of the development of microprocessors with a CPU along with other peripherals.
12) It has no RAM, ROM, Input-Output units, timers, and other peripherals on the chip.It has a CPU along with RAM, ROM, and other peripherals embedded on a single chip.
13) It uses an external bus to interface to RAM, ROM, and other peripherals.It uses an internal controlling bus.
14) The advantage of the microprocessor is that it has a flexible structure.Once a controller is designed the structure is fixed. So, the structure of the microcontroller is not flexible.
15) The program for the microprocessor can be changed for different applications.While in the case of the microcontroller once it is designed, the program is common for that application.
16) The common peripheral interface for the microprocessor is USB, UART, and high-speed Ethernet.the microcontroller peripheral interface is I2C, SPI, and UART.
17) Microprocessor-based systems can run at a very high speed because of the technology involved. The microprocessors are run at higher clock speeds range of 1 GHz to 4 GHz.Microcontroller based systems run up to 200MHz or more depending on the architecture. While in the case of microcontroller, high clock speed is not required 1 MHz to 300 MHz.
18) It’s used for general purpose applications that allow you to handle loads of data.It’s used for application-specific systems.
19) It’s complex and expensive, with a large number of instructions to process.It’s simple and inexpensive with less number of instructions to process.
20) The structure of the microprocessor is flexible.The structure of the microcontroller is not flexible.
Key differences between Microcontroller and Microprocessor

Applications Of Microprocessor And Microcontroller

Application Of MicroprocessorApplication Of Microcontroller

1) Calculators
2) Accounting system
3) Games machine
4) Complex industrial controllers
5) Traffic light
6) Control data
7) Military applications
8) Defense systems
9) Computation systems
10) Computers
11) TV
1) Mobile phones
2) Automobiles
3) CD/DVD players
4) Washing machines
5) Cameras
6) Security alarms
7) Keyboard controllers
8) Microwave oven
9) Watches
10) Mp3 players

MCQ Series and Topics


FAQ

What are application of Microprocessor?

Calculators, Accounting system, Games machine, Complex industrial controllers, Traffic light, Control data, Military applications, Defense systems, Computation systems, Computers, TV

What are the application Of Microcontroller?

Mobile phones, Automobiles, CD/DVD players, Washing machines, Cameras, Security alarms, Keyboard controllers, Microwave oven, Watches, Mp3 players

Is arm a microprocessor or microcontroller?

Arm is microcontroller.

What is difference between Microcontroller and Microprocessor

Microprocessor consists of only a Central Processing Unit, whereas Micro Controller contains a Memory, I/O ports, timers, counters other peripherals along with the CPU or processor.
Microprocessor is used in Personal Computers whereas Micro Controller is used in an embedded system.
Microprocessor uses an external bus to interface to RAM, ROM, and other peripherals, on the other hand, Microcontroller uses an internal controlling bus.

#2 PLC MCQ

Top 10 Multiple choice questions on Programmable logic controller


Question 1: The PLC was invented by.

  • Bill Gates
  • Dick Morley
  • Bill Landis
  • Tod Cunningham

Answer: Dick Morley

Question 2: The first company to build PLCs was.

  • General Motors
  • Allen Bradley
  • Square D
  • Modicon

Answer: Modicon

Question 3: Which part of plc monitors the inputs and makes decisions in a PLC.

  • Sensor
  • CPU
  • Input Module
  • Output Module

Answer: CPU

Question 4: One of the following is an input device.

  • Motor
  • Light
  • Valve
  • Sensor

Answer: Sensor

Question 5: Which one of the following is not a PLC manufacturer.

  • Siemens
  • Mitsubishi
  • Microsoft
  • ABB

Answer: Microsoft

Question 6: Solenoids, lamps, motors are connected to:

  • Analog output
  • Digital output
  • Analog input
  • Digital input

Answer: Digital output

Question 7: In a PLC “I” is used for output and “Q” is used for input.

  • True
  • False
  • None of the above

Answer: False

Question 8: To increase the number of inputs and outputs of the PLC, one can use expansion modules.

  • True
  • False
  • None of the above

Answer: True

Question 9: An example of discrete (digital) control is:

  • Varying the volume of a music system
  • Turning a lamp ON or OFF
  • Varying the brightness of a lamp
  • Controlling the speed of a fan

Answer: Turning a lamp ON or OFF

Question 10: Which of the following statements is NOT correct?

  • The status of each input can be checked from one location and outputs can be forced on and off.
  • All symbols in the RLL represent actual components and contacts present in the control system.
  • PLCs are not as reliable as electromechanical relays in RLL.
  • Input (-| |-) and output (- ( ) -) instruction symbols in the ladder logic represent only data values stored in PLC memory.

Answer: PLCs are not as reliable as electromechanical relays in RLL.

Classification of 8051 Microcontroller

What is Microcontroller ?

Microcontroller is a combination of two words micro and controller, Micro means small in size and controller means a device that can control the operation of any system. So we can say that a microcontroller is a microprocessor with integrated peripherals.

  • A microcontroller is a system on chip it has CPU, I/O ports, Timers, Counters, RAM,ROM on a single chip.
  • In 1981, Intel introduced an 8-bit microcontroller called the 8051.
  • Originally, 8051 Microcontrollers were developed using N-MOS Technology but the use of battery powered devices and their low power consumption, Now a day CMOS Technology (which is famous for its low power consumption).
  • It is widely used in an embedded system, consumer electronics, automotive systems, robotics and security cameras.
  • The peripheral are integrated into a single chip , the over all system cost is very low.
  • The size of the product is small as compare to the microprocessor based system thus very handy .
  • The microcontroller based system is more reliable.
  • MC based system is easy to maintain.
  • All these features available in 40 pin IC.

Classification of Microcontroller

Classification Of Microcontroller According to the Number of Bits

According to bits the microcontroller are 8-bits, 16-bits, and 32-bits microcontroller.

  • 8 Bit Microcontroller: In 8 bit microcontroller the internal bus is 8 bit then the ALU performs arithmetic and logic operations. Example: Intel 8031/8051.
  • 16 Bit Microcontroller: In 16 bit microcontroller executes with greater accuracy and performance in contrast to 8-bit. So 16 bit microcontroller performance is greater compared to 8-bit. 8-bit microcontrollers can only use 8 bits, So its data range of 0×00 – 0xFF (0-255) for every cycle. Where as 16-bit microcontrollers with their data range of 0×0000 – 0xFFFF (0-65535) for every cycle. Example: Intel 8096.
  • 32 Bit Microcontroller: In 32 bit microcontroller uses the 32-bit instructions to carry
    out any arithmetic and logic operations. It is employed mainly in automatically controlled appliances such as office machines, implantable medical appliances, etc. Example: PIC3X

Classification Of Microcontroller According to Memory Devices

According to memory devices Microcontroller are divided into two types.

  1. External Memory Microcontroller
  2. Embedded Memory Microcontroller
  1. External Memory Microcontroller: In this type of microcontroller all functional blocks are not present on a single chip but if we want program memory then externally interfaced using an interfacing circuits and this interfacing circuit is called the glue circuit and the microcontroller is called external memory microcontroller. Example: 8031 has no program memory on the chip is an external memory microcontroller.
  2. Embedded Memory Microcontroller: In this type of microcontroller all functional blocks are present on a single chip is called an embedded microcontroller. Example: 8051 is the best example of embedded memory microcontroller because It having program & data memory, I/O ports, serial communication, counters and timers and interrupts on a single chip.

Classification Of Microcontroller According to Instruction Set

CISC (complex instruction set computer): CISC is stands for Complex Instruction Set Computer. It allows the user to apply one instruction as an alternative to many simple instructions.
RISC (Reduced Instruction Set Computers):  The RISC stands for Reduced Instruction set Computer. It reduces the operation time by shortening the clock cycle per instruction.

Classification Of Microcontroller According to Memory Architecture

According to Memory Architecture there are two type of Microcontroller

  • Harvard Memory Architecture
  • Von Neumann Memory Architecture

Harvard Memory Architecture: In Harvard architecture separate storage and signal buses are provided for different set of instructions and data. This architecture has the entire data storage within the CPU and there is no access available for instruction storage as data.

Von Neumann architecture: In Von Neumann architecture, one data path (or bus) is exists for both instruction and data. So, the CPU does only one operation at a time. It either fetches an instruction from memory, or performs read/write operation on data. So both operations (instruction fetch and a data operation) cannot occur simultaneously because they sharing a common bus.


Different Type of Microcontroller

PIC Microcontroller:

  • PIC Stands for Peripheral Interface Controller is a kind of microcontroller components was used in the development of electronics, computer robotics, and similar devices.
  • Even though the PIC was produced by Microchip technology and based on hardware computing architecture, here the code and data are placed in separate registers to increase the input and output.
  • PIC has a built-in data memory, data bus and dedicated microprocessor for preparing all I/O purposes and methods.

ARM Microcontroller

  • ARM stands for Advanced RISC Machine.
  • It’s the most popular Microcontrollers Programming in the digital embedded system world, and most of the industries prefer only ARM microcontrollers since it consists of significant features to implement products with an excellent appearance.
  • It is cost sensitive and high-performance device which has been used in a wide range of application such as Industrial Instrument control systems, wireless networking and sensors, and automotive body systems, etc.

8051 Microcontroller

In 1981, Intel introduced an 8-bit microcontroller called the 8051.
It is widely used in an embedded system, consumer electronics, automotive systems, robotics and security cameras.
The peripheral are integrated into a single chip , the over all system cost is very lo
The size of the product is small as compare to the microprocessor based system thus very handy
All these features available in 40 pin IC.

MSP Microcontroller

MSP stands for Mixed Signal Processor. It’s the family from Texas Instruments. Built around a 16 -bit CPU.
the MSP is designed for low cost and respectively, low power dissipation embedded statements.
It’s the controller’s appearance is directly related to the 16-bit data bus, and seven addressing modes and the decreased instructions set, which allows a shorter, denser programming code for fast performance.
The Range of Microcontroller is an IC chip that executes programs for controlling other device or machines. It is a micro-device which is used for control of other device machines that’s why it’s called Microcontrollers Programming.

8051 Microcontroller: Introduction, Features and Applications

8051 Microcontroller is a combination of two words micro and controller, Micro means small in size and controller means a device that can control the operation of any system. So we can say that a microcontroller is a microprocessor with integrated peripherals. Microcontrollers are mostly used in embedded systems, engineering projects.

Read more :

The 8051 Microcontroller is one of the most popular and most commonly used microcontrollers in various fields like embedded systems, consumer electronics, automobiles, etc. Microcontroller consists of all features that are found in microprocessors with additional built-in ROM, RAM, I/O ports, Serial ports, Timers, Interrupts, and Clock circuits.

Microcontroller contain combinational circuits and sequential circuits inside it. The Combinational circuits are designed with the help of logic gates to perform logical operations. The sequential circuits are designed by interconnection of combinational circuits and memory or storage elements those are counters, flip-flops, etc.

  • In 1981, Intel introduced an 8-bit microcontroller called the 8051. 
  • It was referred as system on a chip because it had CPU,RAM, On-chip ROM, timers, Counter, serial I/O port, all on a single chip.
  • Originally, 8051 Microcontrollers were developed using N-MOS Technology but the use of battery powered devices and their low power consumption, Now a day CMOS Technology (which is famous for its low power consumption).
  • It is widely used in an embedded system, consumer electronics, automotive systems, robotics and security cameras.
  • The peripheral are integrated into a single chip , the over all system cost is very low.
  • The size of the product is small as compare to the microprocessor based system thus very handy .
  • The microcontroller based system is more reliable.
  • MC based system is easy to maintain.
  • All these features available in 40 pin IC.

Features of 8051 Microcontroller

8051 microcontroller have following features −

  • 128 bytes on-chip data memory (RAM)
  • 4KB bytes on-chip program memory (ROM)
  • 128 user defined software flags
  • 8-bit data bus (bidirectional)
  • 16-bit address bus (unidirectional)
  • 32 general purpose registers each of 8-bit
  • 16 bit Timers (usually 2, but may have more or less)
  • Three internal and two external Interrupts
  • Four 8-bit ports,(short model have two 8-bit ports)
  • 16-bit program counter and data pointer
  • Four register banks
  • 8051 may also have special features like UARTs, ADC etc.

Block Diagram

Block Diagram of Microcontroller

A microcontroller is a microprocessor with integrated peripherals. So we can say that Microcontroller consists of all features that are found in microprocessors with additional built-in ROM, RAM, I/O ports, Serial ports, Timers, Interrupts, and Clock circuits.

Check out the Hindi explanation of 8051 microcontroller Introduction, Feature, and Applications


Difference between Microprocessor & Microcontroller

Difference between Microprocessor & Microcontroller

Microprocessor only have CPU in the chip like most of the Intel Processors but Microcontroller also have RAM, ROM and other peripherals along with the CPU or processor. Both ICs have different applications and have their own advantages and disadvantages. They can be differentiated in terms of Applications, structure, internal parameters, power consumption, and cost.


Applications of 8051 Microcontroller

The 8051 have wide range of applications, but it is mainly used for the embedded system. Following are some applications it is used for.

  1. Consumer Appliances
  2. Home Appliances ( Music Instruments TVs, VCR, Video Games, Oven)
  3. Communication Systems
  4. Office
  5. Automobiles
  6. Aeronautical and Space
  7. Medical Equipment
  8. Defense Systems
  9. Robotics
  10. Industrial Process and Flow Control
  11. Radio and Networking Equipment
  12. Remote Sensing

Check out the explanation of 8051 microcontroller Introduction, Feature, and Applications

 

FAQ’s (Frequently Ask Questions)

What is microcontroller?

Microcontroller is a microprocessor with integrated peripherals. Microcontrollers are mostly used in embedded systems, engineering projects. Microcontroller consists of all features that are found in microprocessors with additional built-in ROM, RAM, I/O ports, Serial ports, Timers, Interrupts, and Clock circuits.

Intel 8051 microcontroller follow which Architecture ?

Intel 8051 is based on Harvard Architecture.

What is 8051 microcontroller block diagram?

The block diagram of the 8051 Microcontroller Architecture shows that 8051 Microcontroller consists of a CPU, RAM (SFRs and Data Memory), Flash (EEPROM), I/O Ports and control logic for communication between the peripherals.

Why 8051 Is Called 8 Bit Microcontroller?

The Intel 8051 is an 8-bit microcontroller which means that most available operations are limited to 8 bits.

List Out The Features Of 8051 Microcontroller?

128 bytes on-chip data memory (RAM)
4KB bytes on-chip program memory (ROM)
128 user-defined software flags
The 8-bit data bus (bidirectional)
16-bit address bus (unidirectional)
32 general purpose registers each of 8-bit
16-bit Timers (usually 2, but may have more or less)
Three internal and two external Interrupts
Four 8-bit ports,(short model have two 8-bit ports)
16-bit program counter and data pointer
Four register banks
8051 may also have special features like UARTs, ADC, etc.

What Is The Width Of Data Bus in 8051 microcontroller?

The Width Of Data Bus in 8051 microcontroller 8-bit data bus.

What Is The Width Of Address Bus in 8051 microcontroller ?

The Width Of Address Bus in 8051 microcontroller 16-bit address bus.

Wiki link

8086 Microprocessor Pin Configuration

8086 was the first 16-bit microprocessor available in 40-pin DIP (Dual Inline Package) chip. Let us now discuss in detail the pin configuration of a 8086 Microprocessor.

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Introduction of 8086 Microprocessor

  • Intel 8086 was the first 16-bit HMOS microprocessor.
  • All the limitation of 8-bit microprocessor is overcome by 16-bit microprocessor.
  • It is a more powerful processor in term of advanced architecture, more processing capability, large memory addressing capability and more powerful instruction set.
  • It is available in 40 pin DIP chip (40 pin IC).
  • It uses a +5V DC supply for its operation.
  • The 8086 uses 20-line address bus. It has a 16-bit data bus.
  • The 20 line of the address bus operate in multiplexed mode. The 16-low order address bus lines have been multiplexed with data and 4 high-order address bus lines have been multiplexed with status signals.

More read on microprocess

Difference between Microprocessor and Microcontroller

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8086 Pin Diagram

8086 was the first 16-bit microprocessor available in 40-pin DIP (Dual Inline Package) chip. Let us now discuss in detail the pin configuration of a 8086 Microprocessor.

A16/S3, A17/S4, A18/S5, A19/S6 :  High order address bus. These are multiplexed with status signals. These lines are high for memory related operation and low for I/O related operation. These are multiplexed with status signal S3 to S4 respectively. The combination of S3 ,S4 determine that which part of memory is to be accessed. Where S6 is always low logic and reserved for future use. S5 for interrupt status

A17/S4A16/S3FUNCTION
00Extra segment access
01Stack segment access
10Code segment access
11Data segment access

•BHE/S7 : BHE signal is enable when data bit are 16 bit it transfer of data over higher order data bus. If it is 1 then data is less than 8 bit.

S2, S1, S0 : Status pins. All are active low pin. These are used by the 8288 bus controller for generating all the memory and I/O operation access control signals. Any change in S2, S1, S0 indicates the beginning of a bus cycle

QS1,QS0 : Queue Status. These signals indicate the status of the internal 8086 instruction queue according to the table shown below

Power supply and frequency signals

It uses 5V DC supply at VCC pin 40, and uses ground at VSS pin 1 and 20 for its operation.

Clock signal

Clock signal is provided through Pin-19. It provides timing to the processor for operations. Its frequency is different for different versions, i.e. 5MHz, 8MHz and 10MHz.

Address/data bus

AD0-AD15. These are 16 address/data bus. AD0-AD7 carries low order byte data and AD8AD15 carries higher order byte data. During the first clock cycle, it carries 16-bit address and after that it carries 16-bit data.

Address/status bus

A16-A19/S3-S6. These are the 4 address/status buses. During the first clock cycle, it carries 4-bit address and later it carries status signals.

S7/BHE

BHE stands for Bus High Enable. It is available at pin 34 and used to indicate the transfer of data using data bus D8-D15. This signal is low during the first clock cycle, thereafter it is active.

Read($\overline{RD}$)

It is available at pin 32 and is used to read signal for Read operation.

Ready

It is available at pin 22. It is an acknowledgement signal from I/O devices that data is transferred. It is an active high signal. When it is high, it indicates that the device is ready to transfer data. When it is low, it indicates wait state.

RESET

It is available at pin 21 and is used to restart the execution. It causes the processor to immediately terminate its present activity. This signal is active high for the first 4 clock cycles to RESET the microprocessor.

INTR

It is available at pin 18. It is an interrupt request signal, which is sampled during the last clock cycle of each instruction to determine if the processor considered this as an interrupt or not.

NMI

It stands for non-maskable interrupt and is available at pin 17. It is an edge triggered input, which causes an interrupt request to the microprocessor.

$\overline{TEST}$

This signal is like wait state and is available at pin 23. When this signal is high, then the processor has to wait for IDLE state, else the execution continues.

MN/MX

It stands for Minimum/Maximum and is available at pin 33. It indicates what mode the processor is to operate in; when it is high, it works in the minimum mode and vice-versa.

INTA

It is an interrupt acknowledgement signal and id available at pin 24. When the microprocessor receives this signal, it acknowledges the interrupt.

ALE

It stands for address enable latch and is available at pin 25. A positive pulse is generated each time the processor begins any operation. This signal indicates the availability of a valid address on the address/data lines.

DEN

It stands for Data Enable and is available at pin 26. It is used to enable Transreceiver 8286. The transreceiver is a device used to separate data from the address/data bus.

DT/R

It stands for Data Transmit/Receive signal and is available at pin 27. It decides the direction of data flow through the transreceiver. When it is high, data is transmitted out and vice-versa.

M/IO

This signal is used to distinguish between memory and I/O operations. When it is high, it indicates I/O operation and when it is low indicates the memory operation. It is available at pin 28.

WR

It stands for write signal and is available at pin 29. It is used to write the data into the memory or the output device depending on the status of M/IO signal.

HLDA

It stands for Hold Acknowledgement signal and is available at pin 30. This signal acknowledges the HOLD signal.

HOLD

This signal indicates to the processor that external devices are requesting to access the address/data buses. It is available at pin 31.

LOCK

When this signal is active, it indicates to the other processors not to ask the CPU to leave the system bus. It is activated using the LOCK prefix on any instruction and is available at pin 29.

RQ/GT1 and RQ/GT0

These are the Request/Grant signals used by the other processors requesting the CPU to release the system bus. When the signal is received by CPU, then it sends acknowledgment. RQ/GT0 has a higher priority than RQ/GT1.

FAQ

Q: What is the 8086 microprocessor?

The 8086 microprocessor is a 16-bit microprocessor chip developed by Intel in the late 1970s. It was the first member of the x86 processor family and marked a significant milestone in the history of personal computers.

Q: When was the 8086 microprocessor released?

The 8086 microprocessor was released by Intel in 1978.

What is the architecture of the 8086 microprocessor?

The 8086 microprocessor follows the complex instruction set computer (CISC) architecture. It has a 16-bit data bus, a 20-bit address bus, and supports a wide range of instructions.

What are the key features of the 8086 microprocessor?

The key features of the 8086 microprocessor include its 16-bit architecture, segmented memory model, support for 1 megabyte of memory, instruction pipelining, and a rich set of instructions.

Q: What is the difference between the 8086 and 8088 microprocessors?

The 8086 and 8088 microprocessors are very similar, but the main difference lies in the external data bus width. The 8086 has a 16-bit data bus, while the 8088 has an 8-bit data bus. This difference affected the performance and cost of systems using these processors.

Q: What is the maximum memory capacity supported by the 8086 microprocessor?

The 8086 microprocessor can address up to 1 megabyte (2^20 bytes) of memory. However, due to its segmented memory model, it requires additional programming techniques to fully utilize the entire memory space efficiently.

Q: What is the segmented memory model in the 8086 microprocessor?

The segmented memory model in the 8086 microprocessor divides the memory into multiple segments of up to 64 kilobytes each. It uses a 16-bit segment register and a 16-bit offset to form a 20-bit physical address, allowing access to a total of 1 megabyte of memory.

Q: What is instruction pipelining in the 8086 microprocessor?

Instruction pipelining is a technique used in the 8086 microprocessor to improve instruction execution speed. It divides the execution of instructions into multiple stages, allowing multiple instructions to be processed simultaneously. This overlapping of instruction execution stages improves overall performance.

Q: What operating systems were compatible with the 8086 microprocessor?

The 8086 microprocessor was compatible with various operating systems, including MS-DOS (Microsoft Disk Operating System), PC DOS, and early versions of Windows. It also served as the foundation for the x86 architecture, which is still widely used today.

Q: What is the legacy of the 8086 microprocessor?

The 8086 microprocessor played a crucial role in the development of personal computers. Its architecture served as the foundation for the x86 processor family, which has evolved over the years and continues to dominate the market. Many modern software applications and operating systems are designed to run on x86-based systems, ensuring the lasting impact of the 8086 microprocessor.

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