Bipolar-Junction Transistors (BJT) Questions and Answers
Bipolar-Junction Transistors (BJT) are essential components in analog and digital circuits. These transistors act as amplifiers or switches and are crucial in designing electronic systems. Many aptitude questions and answers in exams like GATE, ISRO, and DRDO focus on BJT characteristics, configurations, and biasing. This section provides BJT questions with answers and step-by-step solutions to help you understand transistor operation in common-base, common-emitter, and common-collector setups. Practicing these problems through aptitude test practice online strengthens your theoretical knowledge and helps in solving circuit-based questions efficiently during competitive exams.
Learn about BJT operation and characteristics. See also transistor bias circuits and electronic devices
Bipolar-Junction Transistors (BJT)
11. With low-power transistor packages, the base terminal is usually the:
- tab end
- middle
- right end
- stud mount
12. When a silicon diode is forward biased, what is VBE for a C-E configuration?
- voltage-divider bias
- 0.4 V
- 0.7 V
- emitter voltage
13. What is the current gain for a common-base configuration where IE = 4.2 mA and IC = 4.0 mA?
- 16.80
- 1.05
- 0.20
- 0.95
14. If a 2 mV signal produces a 2 V output, what is the voltage gain?
- 0.001
- 0.004
- 100
- 1000
15. The symbol hfe is the same as:
- mca12_1001a1.gif
- mca12_1001b1.gif
- hi-fi
- mca12_1001d1.gif
16. Most of the electrons in the base of an NPN transistor flow:
- out of the base lead
- into the collector
- into the emitter
- into the base supply
17. In a transistor, collector current is controlled by:
- collector voltage
- base current
- collector resistance
- all of the above
19. Often a common-collector will be the last stage before the load; the main function(s) of this stage is to:
- provide voltage gain
- provide phase inversion
- provide a high-frequency path to improve the frequency response
- buffer the voltage amplifiers from the low-resistance load and
20. For a C-C configuration to operate properly, the collector-base junction should be reverse biased, while forward bias should be applied to which junction?
- collector-emitter
- base-emitter
- collector-base
- cathode-anode