DRDO Electronics and Communication Paper
DRDO CEPTAM Electronics & Communications Engineering Model Paper for Senior Technical Assistant B Post
|
S.No. |
Questions |
| 1 | The number 149 in octal code is
(a) 154 (b) 178 (c) 254 (d) 225 |
| 2. | Universal gates are
(a) OR & AND gates (b) NOR & NAND gates (c) NOR & AND gates (d) NAND & OR gates |
| 3 | In full adder, there are
(a) Two binary number inputs and two outputs (b) Three binary digit inputs and two binary outputs (c) Three binary digits inputs and three binary digit outputs (d) NAND & OR gates |
| 4 | The main advantage of PCM system is lower
(a) bandwidth (b) Power (c) Noise (d) None of these |
| 5 | Automatic gain control is used
(a) To maintain the tuning correct (b) To reduce the volume of loud passages of music (c) To increase the amplification at high frequencies (d) To maintain the same volume of output when stations of different strength are received |
| 6 | A rotor of an induction motor cannot run with synchronous speed because
(a) Lenz’ law will be violated (b) Rotor torque will then be zero (c) Induction motor would become synchronous motor (d) Air function prevents it to do so. |
| 7 | Using negative feedback for improvements, which statement is false
(a) Increase bandwidth (b) Increase noise (c) Decreased distortion (d) High input impedance but lower output impedance |
| 8 | An amplifier has input impedance of 4 KOhms and output impedance of 80 KOhms. It is used in negative feedback circuit with 10% feedback. If open loop gain is 90, the closed loop input and output impedances are
(a) 40 KOhms and 8 KOhms respectively (b) 4 KOhms and 80 KOhms respectively (c) 0.4 KOhms and 800 KOhms respectively (d) 8 KOhms and 160 KOhms respectively |
| 9 | In a current transformers
(a) The number of turns in primary and secondary windings are nearly equal (b) The number of turns in primary turns is very small as compared to number of secondary turns (c) The number of secondary turns is very small as compared to the number of primary turns (d) Either (a) or (c) |
| 10 | The turn ration of a transformer is 20:1, if a load of 10 Ohms is connected across the secondary, what will be the effective resistance seen looking into the Primary?
(a) 2 K Ohms (b) 4 K Ohms (d) 8 K Ohms (d) 32 K Ohms |
| 11 | Which statement is correct?
(a) BJT and MOSFET are current controlled devices (b) BJT is voltage controlled and MOSFET is current controlled device (c) BJT and MOSFET are voltage controlled devices (d) BJT is current controlled and MOSFET is voltage controlled device |
| 12 | To satisfy the sampling theorem, a 100 Hz sine wave should be sampled at
(a) 10 Hz (b) 100 Hz (c) 200 Hz (d) 50 Hz |
| 13 | In a junction transistor, recombination of electrons and holes occurs in
(a) base region only (b) emitter region only (c) Collector region only (d) All the 3 regions |
| 14 | The maximum power dissipation capacity of a transistor is 50 mW. If the collector emitter voltage is 10 V. What is the safe collector current that can be allowed through the transistor?
(a) 5 mA (b) 2.5 mA (c) 10 mA (d) 25 mA |
| 15 | In a sequential circuit, the outputs at any instant of time depends
(a) Only on the inputs present at that instant of time (b) On past outputs as well as present inputs (c) Only on the past inputs (d) Only on the present outputs |
| 16 | How many FFs are requied to build a binary counter circuit to count from 0 to 1023.
(a) 1 (b) 6 (c) 10 (d) 24 |
| 17 | The address bus width of a memory of size 1024 x 8 bits is
(a) 10 bits (b) 13 bits (c) 8 bits (d) 18 bits |
| 18 | The number of comparators in a parallel conversion type 8 –bit A to D converter is
(a) 8 (b) 16 (c) 225 (d) 127 |
| 19 | An analog voltage is in the range of 0 to 8 is divided in eight equal intervals for conversion to 3-bit digital output. The maximum quantization error is
(a) 0 V (b) 0.5 V (c) 1 V (d) 2 V |
| 20 | The frequency deviation produced in a VHF carrier by a signal of 100 Hz is 50 kHz. The frequency modulation index is
(a)100 radians (b) 250 radians (c) 500 radians (d) 750 radians |
Leave a Reply