📡 Electronics and Communication Engineering (ECE) Solved MCQs with Answers

Practice 406 approved 📡 Electronics and Communication Engineering (ECE) questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

406 solved MCQs

A ring counter with 5 flip flops will haveAnswer: 5 states In the expression A + BC, the total number of minterms will beAnswer: 5 Which of the following is non-saturating?Answer: ECL The number of digits in octal system isAnswer: 8 The access time of a word in 4 MB main memory is 100 ms. The access time of a word in a 32 kb data cache memory is 10 ns. The average data cache bit ratio is 0.95. The efficiency of memory access time isAnswer: 14.5 ns An 8 bit DAC has a full scale output of 2 mA and full scale error of ± 0.5%. If input is 10000000 the range of outputs isAnswer: 994 to 1014 μA Decimal 43 in hexadecimal and BCD number system is respectively.Answer: 2B, 01000011 An AND gate has two inputs A and B and one inhibit input 3, Output is 1 ifAnswer: A = 1, B = 1, S = 0 The greatest negative number which can be stored is 8 bit computer using 2's complement arithmetic isAnswer: - 128 The basic storage element in a digital system isAnswer: flip flop In a ripple counter,Answer: whenever a flip flop sets to 1, the next higher FF toggles A 12 bit ADC is used to convert analog voltage of 0 to 10 V into digital. The resolution isAnswer: 2.44 mV A full adder can be made out ofAnswer: two half adders and a OR gate The output of a half adder isAnswer: SUM and CARRY Which device has one input and many outputs?Answer: Demultiplexer A carry look ahead adder is frequently used for addition becauseAnswer: it is faster In register index addressing mode the effective address is given byAnswer: sum of the index register value and the operand Zero suppression is not used in actual practice.Answer: False A counter type A/D converter contains a 4 bit binary ladder and a counter driven by a 2 MHz clock. Then conversion timeAnswer: 8 μ sec The number of distinct Boolean expression of 4 variables isAnswer: 65536 The fixed count that should be used so that the output register will represent the input for a 6 bit dual slope A/D converter uses a reference of -6v and a 1 MHz clock. It uses a fixed count of 40 (101000).Answer: 000110 A memory system of size 16 k bytes is to be designed using memory chips which have 12 address lines and 4 data lines each. The number of such chips required to design the memory system isAnswer: 8 In a 7 segment display, LEDs b and c lit up. The decimal number displayed isAnswer: 1 In a BCD to 7 segment decoder the minimum and maximum number of outputs active at any time isAnswer: 2 and 7 A three state switch has three outputs. These areAnswer: low, high, floating 1's complement of 11100110 isAnswer: 00011001 Mechanical impedance is the ratio ofAnswer: rms force to rms velocity Whether a linear system is stable or unstable that itAnswer: is a property of the system only If a system is to follow arbitrary inputs accurately the bandwidth should beAnswer: large Assertion (A): Potentiometers can not be used as error detectors in position control systems. Reason (R): The resolution of a potentiometer places an upper limit on its accuracyAnswer: R is correct but A is wrong