Physics

Semiconductors and Diodes

461 Questions

Semiconductors and diodes form the foundation of modern electronics, covering topics like intrinsic carrier concentration and Zener breakdown. Questions often explore the characteristics of bipolar junction transistors (BJT) and the properties of doped silicon materials. This topic is crucial for physics and electronics engineering competitive exams.

Zener diode breakdownBJT circuit analysisIntrinsic carrier concentrationDoping in semiconductorsEmitter follower circuit

Semiconductors and Diodes Questions

Multiple choice

Tri-state BJT works as a buffer. What are the outputs of this buffer?

  1. Level 1, level 0, short

  2. Level 1, level 0, high resistance

  3. Level 1, level 0, level 1

  4. Level 1, level 0, level 0

  5. Level 0, high resistance, high resistance
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tri-state buffers provide isolation to the connecting device from the bus when in third state. High resistive feature provides the required isolation.

Multiple choice

Which of the following can be sensed by a semiconductor?

  1. Conductivity

  2. Resistance

  3. Power

  4. Magnetism

  5. Biasing
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Magnetism is a class of physical phenomena that includes forces exerted by magnets on other magnets. It has its origin in electric currents and the fundamental magnetic moments of elementary particles.

Multiple choice

Majority carriers in a n-type material is/are __________.

  1. holes

  2. dopants

  3. power

  4. electrons

  5. forward bias
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An electron has no known components or sub-structure. It is generally thought to be an elementary particle.  An electron has a mass, which is approximately 1/1836 that of the proton.

Multiple choice

What are responsible for the depletion region?

  1. Doping

  2. Ions

  3. Electrons

  4. Diffusion

  5. Barrier potential
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Diffusion is one of several transport phenomena that occur in nature. A distinguishing feature of diffusion is that it results in mixing or mass transport without requiring bulk motion.

Multiple choice

The gain of a BJT amplifier drops down sharply when the input signal frequency is raised to a very high value. Why does it happen?

  1. Internal capacitance of the BJT

  2. Coupling capacitor at the base of the BJT

  3. Coupling capacitor at collector of the BJT

  4. Biasing resistors

  5. By pass capacitor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The junction layers at BE, BC and the portion at CE offers capacitive effect to the flow of electrons in BJT when properly exited. This capacitive effect becomes prominently high to reduce the flow of electrons during the high frequency signal's cycle time. Due to this, the gain falls (current reduces due to decrease in flow of electrons from C to E).

Multiple choice

Both the inputs of an OPAMP are grounded. The Vcc and Vee are applied to OPAMP. The OPAMP shows an output voltage of 10 mv. Which one of the options explains this correctly?

  1. Output should be 0mv and OPAM is faulty

  2. Due to input offset voltage characteristic of OPAMP

  3. Output offset characteristic

  4. By having very high CMRR

  5. Both (1) and (4)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Output offset characteristic is defined as: it is the voltage (may be 10 mv) produced by the OPAMP when its both inputs are grounded. This is not a faulty condition, rather some time it is required  in some applications.

Multiple choice

In which line coding scheme does the positive voltage defines bit 1 and the zero voltage defines bit 0 but not return to zero at the middle of the bit?

  1. Bipolar AMI line coding scheme

  2. Bipolar pseudoternary line coding scheme

  3. Unipolar NRZ line coding scheme

  4. Complexity

  5. DC components
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Here, the positive voltage defines bit 1 and the zero voltage defines bit 0 and the signal does not return to zero at the middle of the bit.