Multiple Choice Quiz: Semiconductors

Zener diodes exhibit:

(a) an abrupt reverse breakdown
(b) a gradual forward breakdown
(c) no breakdown at all

In a semiconductor diode, the depletion region is removed when:

(a) the diode is in its forward conducting state
(b) the diode is in its reverse non-conducting state
(c) there is no potential difference between the anode and cathode

The following data refers to an experiment carried out on a Zener diode:

The Zener voltage will be between:

(a) 1 V and 2 V
(b) 2 V and 3 V
(c) 3 V and 4 V

Which one of the following is TRUE of a two-input OR gate?

(a) a logic 1 output will be produced only when both inputs are at logic 1
(b) a logic 1 output will be produced when only one of the two inputs is at logic 1
(c) a logic 1 output will be produced when one or both of the two inputs is at logic 1

The truth table shown is for a two-input:

(a) NAND gate
(b) NOR gate
(c) Exclusive-OR gate

The forward threshold voltage for a germanium diode is about:

(a) 0.2 V
(b) 0.4 V
(c) 0.6 V

The truth table shown is for a two-input:

(a) NAND gate
(b) NOR gate
(c) Exclusive-OR gate

The typical operating current for a light-emitting diode is approximately:

(a) 1 to 5 mA
(b) 5 to 20 mA
(c) 20 to 500 mA

Which one of the following Boolean expressions is correct for an exclusive-OR gate?

(a) A +
(b) A . B + .
(c) A . + B.

In normal (conducting) operation, the voltage that will appear between the base and emitter of an NPN bipolar junction transistor will be approximately:

(a) 0.15 V
(b) 0.25 V
(c) 0.65 V

The term 'covalent bonding' refers to:

(a) the introduction of an impurity
(b) the sharing of valence electrons
(c) the generation of surplus electrons

When a diode is in its non-conducting state it has:

(a) a very low resistance
(b) a very high resistance
(c) no resistance at all

The zone in a semiconductor diode where no free charge carriers exists is known as the:

(a) anode region
(b) cathode region
(c) depletion region.

It is required to change a logic 0 state into a logic 1 state, and vice versa.

The logic gate required to do this is known as:

(a) a buffer
(b) an inverter
(c) an exclusive-OR gate

The collector current in a bipolar junction transistor is 2 mA when the base current is 0.1 mA. Which one of the following gives the emitter current?

(a) 1.9 mA
(b) 2.1 mA
(c) 20 mA

The Boolean expression for the output of a two-input AND gate is:

(a) A B
(b) A . B
(c) A + B

In an NPN bipolar junction transistor the connections are arranged as follows:

(a) base to P-type, emitter to N-type material, collector to N-type
(b) base to N-type, emitter to N-type material, collector to P-type
(c) base to N-type, emitter to P-type material, collector to N-type

The collector current in a bipolar junction transistor is 2 mA when the base current is 0.1 mA. Which one of the following gives the value of common-emitter current gain?

(a) 1.9
(b) 2.1
(c) 20

The forward threshold voltage for a silicon diode is about:

(a) 0.15 V
(b) 0.25 V
(c) 0.65 V

When a diode is in its conducting state:

(a) current flows from anode to cathode
(b) current flows from cathode to anode
(c) no current flows in the diode

In a metal-cased bipolar transistor, which of the three connections of the transistor are often connected directly to the conducting case?

(a) base
(b) collector
(c) emitter

Which one of the following gives the relationship between the three currents flowing in a bipolar junction transistor?

(a) I_E = I_B + I_C
(b) I_B = I_E + I_C
(c) I_C = I_B + I_E

How many electrons are present in the outer valence shell of a silicon atom?

(a) 1
(b) 2
(c) 4

The three terminals of a bipolar junction transistor are known as:

(a) source, gate, collector
(b) emitter, gate, collector
(c) emitter, base, collector

In its pure state, silicon has the properties of:

(a) a conductor
(b) an insulator
(c) a semiconductor