EAC 4: Vacuum and Semiconductor Theory

Flashcards for EAC 4: Vacuum and Semiconductor Theory

How many electrons are there in the fourth orbit of a copper atom?

A.     1                            C. 2

B.     3                            D. 4

1

The maximum permissible number of electrons in the third orbit is

A.     8                            C. 18

16                                D. 32

18

Valence orbit is the other term for .

A.     Outer orbit              C. 4^th orbit

B.     3^rd orbit                   D. 2^nd orbit

Outer orbit

K shell means _.

A.     1^st orbit                   C. 3^rd orbit

B.     2^nd orbit                  4. 4^th orbit

1st orbit

The electrons in the largest orbit travel _ than the electrons in the smaller orbits.

A.     More slowly            C.  A bit slower

B.     Faster                    D. Very fast

Faster

What orbit controls the electrical properties of the atom?

A.     Valence orbit          C. Fourth orbit

First orbit                      D. M shell

Valence orbit

What substance contains atoms with several bands of electrons but with only one valence electrons?

A.     Insulator                 C. Semiconductor

B.     Conductor               D. Dielectric

Conductor

Pure silicon crystal atoms contain how many valence electrons as a result of covalent bonding?

A.     1                            C. 8

B.     4                            D. 16

8

Each atom in a silicon crystal has how many electrons in its valence orbit?

A.     8                            C. 32

B.     2                            D. 4

4

Lifetime is the amount of time between the creation and disappearance of a/an:

A.     Free electron          C. Neutron

B.     Proton                    D. Ion

Free electron

Which is a donor atom?

A.     Trivalent                 C. Aluminum

B.     Boron                     D. Pentavalent

Pentavalent

Silicon that has been doped with a pentavalent impurity is called a/an:

A.     N-type semiconductor

B.     P-type semiconductor

C.     Intrinsic semiconductor

D.     Extrinsic semiconductor

N-type semiconductor

In an n-type semiconductor, free electrons are called __.

A.     Minority carriers

B.     Valence electrons

C.     Majority carriers

D.     Charge carriers

Majority carriers

What is the barrier potential of germanium at 25 oC?

A.     0.7V                       C. 0.3V

B.     0.5V                       D. 1.3V

0.3V

An extrinsic semiconductor is a __.

A.     Doped semiconductor

B.     Pure semiconductor

C.     Good insulator

D.     Superconductor

Doped semiconductor

Each pair of positive and negative ions at the junction is called a/an .

A.     Anion                      C. Cation

B.     Positron                  D. Dipole

Dipole

In an pn-junction diode under reverse biased, the magnitude of electric field is maximum at:

A.     The edge of depletion region on the n-side.

B.     The edge of depletion region on the p-type.

C.     The center of the n-type region.

D.     The PN-junction.

The PN-junction.

Under low level injection assumption, the injected minority carrier current for an extrinsic semiconductor is essentially the:

A.     Diffusion                 C. Drift current

B.     Induced current       D. Recombination current

Diffusion

The band gap of silicon at room temperature:

A.     1.3 eV                    C. 1.1 eV

B.     0.7 eV                    D. 1.4 eV

1.1 eV

What causes the depletion region?

A.     Doping                   C. Barrier potential

B.     Diffusion                 D. Recombination

Diffusion

Another name for vacuum tube diode.

A.     Thyratron               C. Audion

B.     Fleming valve         D. Detector

Fleming valve

Which terminal of the tetrode is nearest to its anode?

A.     Screen grid             C. Cathode

B.     Supressor grid        D. Control grid

Screen grid

It is the maximum permissible reverse voltage for the diode.

A.     PIV                         C. Barrier voltage

B.     Maximum voltage    D. Tolerable voltage

PIV

What is another name for clamper?

A.     Slicer                     C. Clipper

B.     Limiter                    D. DC restorer

DC restorer

The process of converting AC to pulsating DC signal?

A.     Recombination        C. Charging

B.     Rectification           D. Filtering

Rectification

A full wave rectifier circuit utilizing a full input cycle has a ripple frequency in its output equal to:

A.     60 Hz                     C. 110 Hz

B.     120 Hz                    D. 220 Hz

120 Hz

What is the maximum efficiency of full wave rectifier?

A.     50%                       C. 40.6%

B.     81.2%                     D. 100%

81.2%

It is the remaining variation in the output of a power supply filter.

A.     Residual voltage     C. Offset voltage

B.     Ripple                     D. Induced voltage

Ripple

What type of bias is required for an LED to produce luminescence?

A.     Reversed                C. Forward

B.     Fixed                      D. Zero

Forward

A dc voltage supply is measured at 50V and drops to 45V when load is connected. What is the value of voltage regulation?

A.     5%                         C. 60%

B.     50%                       D. 11.11%

11.11%

When the peak output voltage is 100V, the PIV for each diode in the full wave center tapped rectifier is:

A.     100V                      C. 141V

B.     200V                      D. 50V

100V

Find the dc voltage from a full wave rectifier with 120V peak rectified voltage.

A.     60V                        C. 76.39V

B.     7.64V                     D. 6.0V

76.39V

Find the band gap energy when a light of wavelength 1240 nm is incident on it.

A.     1 eV                       C. 1.3 eV

B.     2 eV                       D. 5 eV

1 eV

When the rms output voltage of a bridge full wave rectifier is 20V, the peak inverse voltage across the diodes, neglecting the diode drop, is:

A.     20 V                       C. 28.3 V

B.     40 V                       D. 56.6 V

28.3 V

A certain power supply filter produces an output with a ripple of 100 mV peak-to-peak and a dc value of 20 V. The ripple factor is:

A.     0.05                        C. 0.00005

B.     0.005                      D. 0.02

0.005

A 60 V peak full wave rectified voltage is applied to a capacitor-input filter. If f=120 Hz, RL=10 kΩ, and C=10 uF, the ripple voltage is:

A.     0.6 V                      C. 5.0 V

B.     6 mV                      D. 2.88 V

2.88 V

The average value of the input of a half wave rectified voltage with a peak value of 200 V is:

A.     63.7 V                    C. 141 V

B.     127.2 V                   D. 0 V

63.7 V

The average value of a full wave rectified voltage with a peak value of 75 V is:

A.     53 V                       C. 37.5 V

B.     47.8 V                    D. 23.9 V

47.8 V

A 10 Vp-p sinusoidal voltage is applied across a silicon diode and series resistor. The maximum voltage across the diode is:

A.     9.3 V                      C. 5 V

B.     0.7 V                      D. 4.3V

0.7 V

If the input voltage to a voltage tripler has an rms value of 12 V, the dc output voltage is approximately.

A.     36 V                       C. 33.9 V

B.     50.9 V                    D. 32.4 V

33.9 V