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)
1. Three different Q points are shown on a dc load line. The upper Q point represents the:
- minimum current gain
- intermediate current gain
- maximum current gain
- cutoff point
2. A current ratio of IC/IE is usually less than one and is called:
- beta
- theta
- alpha
- omega
3. With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be:
- open
- infinite
- low resistance
- high resistance
4. In a C-E configuration, an emitter resistor is used for:
- stabilization
- ac signal bypass
- collector bias
- higher gain
5. Voltage-divider bias provides:
- an unstable Q point
- a stable Q point
- a Q point that easily varies with changes in the transistor's current gain
- a Q point that is stable and easily varies with changes in the transistor’s current gain
6. To operate properly, a transistor's base-emitter junction must be forward biased with reverse bias applied to which junction?
- collector-emitter
- base-collector
- base-emitter
- collector-base
7. The ends of a load line drawn on a family of curves determine:
- saturation and cutoff
- the operating point
- the power curve
- the amplification factor
8. The C-B configuration is used to provide which type of gain?
- voltage
- current
- resistance
- power
9. A transistor may be used as a switching device or as a:
- fixed resistor
- tuning device
- rectifier
- variable resistor
10. A collector characteristic curve is a graph showing:
- emitter current (IE) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VC) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VCC) with (VBB) base bias voltage held constant