Semiconductor-Diodes-Voltage-Dividers

Intrinsic semiconductor material is characterized by a valence shell of how many electrons?

• A.1

• B.2

• C.4

• D.6

Answer explanation

The semiconductor materials are in the group 4, and all of them have 4 valence electron in its outermost shell.

One eV is equal to ________ J.

• A. 6.02 × 10^23

• B. 1.6 × 10^-19

• C. 6.25 × 10^18

• D. 1.66 × 10^-24

Answer explanation

This is the energy transferred when an electron moves between two points with a potential difference of 1volt between them. 1 eV = 1.6 x 10^-19 J

The diode ________.

• A. is the simplest of semiconductor devices

  
  

• B. has characteristics that closely match those of a simple switch

  
  

• C. is a two-terminal device

  
  

• D. All of the above

  
  

Answer explanation

D. All of the above

Option A says that it is the simplest semiconductor formed of a p-type and n-type semiconductor.

Option B says that it acts like a switch since it has two states forward bias and reverse bias so forward bias acts high state that is on and in reverse bias it low state that is offWe know that

Option C is also true.

 It is not uncommon for a germanium diode with an Is in the order of 1-2 uA at 25°C to have leakage current of 0.1 mA at a temperature of 100°C.

• A. True

• B. False

Answer explanation

Answer: A. True

Id=Is e^kT/V, where k is the Boltzmann's Constant and k=1.38x10^-23, the T is the temperature in kelvin = T in degree Celsius+273 and V is the voltage across the diode. As it is the germanium diode, we take V=0.3V. Then calculate the value of Id at 298 kelvin i.e. at 25 degree Celsius. Then the value of Id doubles itself for every 10 degree rise in the temperature. Thus, the value of Id obtained will be equal to 0.1x10^-3A. Also, the diode can operate at this temperature. Therefore, it is not uncommon to have this reading.

What does a high resistance reading in both forward- and reverse-bias directions indicate?

• A. A good diode

• B. An open diode

• C. A shorted diode

• D. A defective ohmmeter

Answer explanation

Answer: B. An open diode

When there is very high resistance across the circuit it means that the current value is negligible or no current flows through the circuit and then no current flows at very high resistance the circuit is open.

 Which capacitance dominates in the reverse-bias region?

• A. depletion

• B. conversion

• C. Diffusion

• D. None of the above

Answer explanation

Answer: A. depletion

In reversed bias, depletion width increases hence depletion capacitance dominates.

While in forward bias, depletion width decreases and diffusion capacitance dominates.

Which capacitance dominates in the forward-bias region?

• A. depletion

• B. conversion

• C. Diffusion

• D. None of the above

Answer explanation

Answer: C. diffusion

In reversed bias, depletion width increases hence depletion capacitance dominates.

While in forward bias, depletion width decreases and diffusion capacitance dominates.

What is the state of an ideal diode in the region of nonconduction?

• A. An open circuit

• B. A short circuit

• C. Unpredictable

• D. Undefined

Answer explanation

Answer: A. An open circuit

Conduction region meant for the area where the flow of electrons is allowed. Non conduction region means where flow of electrons is blocked, so no current. The region where no current is passing is considered as open circuit.

How many orbiting electrons does the germanium atom have?

• A. 4

• B. 14

• C. 32

• D. 41

Answer explanation

Answer: C. 32

The electrons in the different orbits of the germanium are called orbiting electrons of the germanium. It has 2, 8, 18, 4 electrons in 1st, 2nd, 3rd and 4th orbits so total 32 then answer is 32.

How many terminals does a diode have?

• A. 1

• B. 2

• C. 3

• D. 4

Answer explanation

Answer: B. 2

A diode is basically a p-n junction device where p-type (positive) is one terminal and n-type (negative) is another terminal.