Semiconductor Electronics Test

Semiconductor Electronics Test

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Two identical germanium diodes are connected in series opposition. A 10V battery is impressed upon this series arrangement. What will be the voltage across each diode room temperature if the Zener breakdown voltage of each diode is 9.8V?

a. V_D1= 0.2V , V_D2 = 9.8V

b. V_D1 = 10V , V_D2 = 0V

c. V_D1 = 0V , V_D2 = 10V

d. V_D1 = 9.8V , V_D2 = 0.2V

Which one of the following is Shockley's equation?

a. I_D = I_DSS [1-V_GS/V_P]²

b. I_DSS = I_D [1-V_GS/V_P]²

c. V_P = I_P [1-V_GS/I_DSS]²

d. V_GS = V_P [1-I_D/I_DSS]²

An SCR combines the features of_____.

a. a rectifier and an amplifier

b. a rectifier and a transistor

c. a rectifier and an oscillator

d. a rectifier and an inverter

The required gain of an amplifier for sustained oscillation in the wein bridge oscillator is _____.

a. A 2

b. A 1

c. A 3

d. None of the above

The maximum value of AC voltage appearing across the secondary of a transformer in a bridge circuit using a vacuum tube is 400 v. The peak inverse voltage of the diode should be _____.

a. 200 v

b. 800 v

c. 400 v

d. 600 v

The impedance of a parallel tuned circuit at resonance is _____.

a. 0

b. low

c. very high

d. very low

Which of the following parameters is a measure of a vacuum tube's amplification capability?

a. transresistance

b. impedance

c. conductance

d. transconductance

At parallel resonance, a tuned circuit offers an impedance of _____.

a. C/LR

b. R/LC

c. L/CR

d. 2L/CR

Radio frequencies have their range above _____.

a. 20KHZ

b. 50KHZ

c. 100KHZ

d. 200KHZ

The stability factor of a biasing circuit is 10. What does it mean?

a. Ic changes 10 times as munch as any change in Ico(leakage current)

b. Ib changes 10 times as much as any change in Ico

c. Ie change 10 times as munch as any change in Ico

The maximum efficiency of a full wave rectifier is _____.

a. 40%

b. 81.2%

c. 90%

d. 99%

If the collector supply voltage is 10v, the collector cut off voltage under D.C conditions will be _____.

a. 5v

b. 10v

c. 20v

d. 30v

The overall gain of a multistage amplifier is 140. When negative feedback is applied, the gain is reduced to 17.5. The fraction of the output that is feedback to the input will be _____.

a. 1/30

b. 1/20

c. 1/10

d. 1/5

The complementary MOS(CMOS) uses _____.

a. only n-channel devices in the circuit

b. only p- channel devices in the circuit

c. both n and p channel devices in the circuit

d. None of the above

The most commonly used semiconductor in solid state devices is _____.

a. germanium

b. carbon

c. silicon

d. phosphorus

Tuning is generally accomplished by varying _____.

a. L(inductor)

b. C(capacitor)

c. both L and C

d. R(resistor)

We have to match a 16-ohm speaker to an amplifier so that the effective load resistance is 10 KΩ. What should be the transformer turn ratio?

a. N_p/N_s=50

b. N_p/N_s=25

c. N_p/N_s=75

d. N_p/N_s=12.5

Which coupling does the final stage of a multistage amplifier use?

a. direct

b. transformer

c. RC

d. None of the above

Vacuum tubes are _____.

a. linear devices

b. non-linear devices

c. both linear and non-linear under different conditions

If in a transistor , I_c = 9.5mA , I_e = 10mA , the value of α will be _____.

a. 0.95

b. 10

c. 9.5

d. 0.095

The range of LC oscillators is _____.

a. 20 HZ to 100KHZ

b. 10 HZ to 20 HZ

c. 100KHZ to a few GHZ

A three-stage amplifier has a first-stage voltage gain of 100, a second stage voltage gain of 200 and a third stage gain of 400. The total voltage gain in db will be _____.

a. 130 dB

b. 140 dB

c. 132 dB

d. 138 dB

Which of the following conditions must a transistor fulfill to act as an amplifier?

a. Base-emitter junction reverse biased and base-collector junction forward biased

b. Base-emitter junction forward biased and base-collector junction reverse biased

c. Emitter-collector junction forward biased and base- collector junction reverse biased

d. Base-collector junction forward biased and emitter-collector junction reverse biased

Hartley oscillator is _____.

a. an RC oscillator

b. an LC oscillator

c. a Crystal oscillator

The output characteristics of an FET closely resemble the plate characteristics of a________ valve.

a. diode

b. triode

c. tetrode

d. pentode

The slope of the D.C load line of a transistor circuit having a collector load Rc is _____.

a. Rc

b. 1/Rc

c. -1/Rc

d. 2Rc

In the d.c. equivalent circuit of a transistor amplifier , the capacitors are regarded as _____.

a. Open

b. Short

c. Sometimes open and sometimes short

d. Unchanged

In the collector feedback biasing, β = 57 , R_C = 1 kΩ , I_B = 60µA and V_CB = 4.5V. The value of the stability factor will be _____.

a. 30.4

b. 32.9

c. 57

d. 4.5

If the input to an integrating circuit is a square wave, the output will be _____.

a. triangular

b. rectangular

c. saw-tooth

d. spiked

Which of the following configurations of a transistor is preferred as an amplifier?

a. common-collector

b. common- base

c. common-emitter

d. None of the above

A D.C milliammeter connected to a half-wave rectifier supplying a maximum current of 10mA will read _____.

a. 10 mA

b. 20 mA

c. 5 mA

d. 3.18 mA

A triac can pass a portion of _____.

a. positive half-cycle through the load

b. negative half-cycle through the load

c. both positive and negative half-cycles through the load

d. None of the above

Which one of the following is a non-feedback type oscillator?

a. Wein bridge oscillator

b. Hartley oscillator

c. UJT relaxation oscillator

d. Colpitts oscillator

If in a transistor I_E = 10.5mA , I_C = 10mA,the value of β will be _____.

a. 0.2

b. 200

c. 100

d. 20

A transistor amplifier has 4v,2mA as the operating point. For faithful amplification, the collector current due to signal alone should not exceed _____.

a. 2mA

b. 1mA

c. 4mA

d. 8mA

A vacuum tube conducts current _____.

a. from the cathode to the anode

b. from the anode to the cathode

c. in both the above directions

d. alternately in both directions

The input and output voltages of a CE transistor amplifier are _____.

a. in phase

b. 90° out of phase

c. 180° out of phase

d. 120° out of phase

If the input to a differentiating circuit is a square wave, the output will be _____.

a. rectangular

b. spiked

c. triangular

d. sinusoidal

If a circuit of full-wave centre-tapped rectifier with capacitor filter employs a load R_L = 100Ω, and C = 1050µF and the frequency is 50HZ , what would be the ripple factor?

a. 40%

b. 30%

c. 22%

d. 27%

Which of the following is used to provide current in vacuum tubes?

a. protons

b. ions

c. electrons

d. neutrons