EET 2220 Final Exam Review
VCE equals what when transistor is in saturation
0.2V
Barrier potential for germanium is
0.3V
Barrier potential for silicon is
0.7V
Shorted diode will read
0V
a shorted diode reads what V?
0V
ideal diode approximation gives what voltage?
0V forward voltage
the collector resistance in a transistor amplifier is open and the dc voltage at the collector will be
0Volts
if the positive lead of an ohmmeter is on the cathode and negative is on the anode, what would indicate a defective diode?
0Ω and ∞Ω for reverse
common base amplifier has current gain of
1
if an input frequency is 60Hz, the output frequency in a bridge rectifier is
120Hz ; fout = 2fin
BJT transistors have how many PN junctions
2
max number of electrons that can be in the shell closest to the nucleus is
2 electrons
a bipolar junction transistor has how many regions of operation?
3
the typical max Vf in an LED is between 1.2V and
3.2V
Silicon and Germanium contain how many valence electrons?
4
Typical value of reverse breakdown voltage in a diode is
50V or larger
the value of half-wave rectified output voltage is _________ of Vp
70.7%
A reverse diode has _________ connected to the positive side of the source and ________ to negative side of the source
Cathode, anode
T/F Laser diode emits monochromatic light
FALSE; emits incoherent light of a single color
T/F Semiconductor of the p-type has many free electrons
False; p-type has few free electrons
T/F A molecule is the smallest particle of an element that retains the characteristics.
False; the atom is the smallest particle
valence have ______ energy level
Highest
IE =
IC + IB
Ic =
IE - IB
ßdc =
Ic/IB
Common Emitter Av =
IeRc / Icr'e
Zener voltage at test current is measured
Izt
Darlington pair uses an NPN and
NPN transistor
a Sziklai pair uses a PNP and
NPN transistor
if a circuit is in saturation, it will get closer to linear if
RB is increased
Rout =
Rc
what diode has a metal to semiconductor junction?
Schottky diode
which statement best describes a p-type semiconductor?
Silicon with trivalent impurity atoms added.
T/F silicon doped with impurities is used in the manufacture of semiconductor devices
TRUE
T/F the regulating ability of a zener diode depends upon its ability to operate in a breakdown condition
TRUE; how well the zener regulates has to do with it's operation in breakdown.
Av =
Vout/Vin
high input impedance amplifier is
a common collector
zener diode operates like
a rectifier diode
if IB > IB(min) the circuit is
active
the load resistance in a filtered power supply varies, the output voltage
also varies
BJT requires what junction to be reverse bias?
base collector
Collector current is controlled by
base current
A diode limiter can also be called a
clipper
the region in a transistor that dissipates the most heat is the
collector
half wave rectifier
conducts for 180 degrees of the input cycle
PIN diode, when reverse biased acts like a constant
constant capacitance
reverse bias prevents
current through the diode
load resistance decreases in a regulator, the zener current
decreases
The difference in energy level between the valence band and conduction band is
energy gap
a photodiode
exhibits an increase in reverse current with light intensity
NPN majority carriers are
holes
LED color is determined by
impurities added during doping to control wavelength
if IB < IB(min) the circuit is
in saturation
why doesn't germanium get use in modern electronics?
it has high temperature instability
Varactor diode changes
its capacitance with voltage
the DC current through each diode in a bridge rectifier equals
load current
common emitter amplifier has high input impedance, high voltage gain and
low current gain
an emitter follower does NOT have
low impedance
What is a semiconductor?
materials with conductive properties that are between conductor and insulator
a reverse voltage is decreased, the depletion region
narrows
is copper a semiconductor?
no; copper is not a semiconductor
if a forward bias LED is on but no light is showing, the diode is
open
silicon diode measures high value of resistance with the meter leads in both positions, the diode might be
open
in what type semiconductor are holes the majority carriers?
p-type
photodiode is usually what bias
photodiode is reverse biased
NPN BJT requires base to be ___________ w/ respect to the emitter, and ________ to the collector
positive, negative
if a diode is non-conducting it is in what bias?
reverse bias
small current when a diode is reverse biased
reverse leakage current
a non conducting diode is
reversed bias
electrons orbiting the nucleus of an atom are grouped into energy bands known as
shells
when the DMM has a small ohm reading, it is likely the diode is
shorted
what does the radiation pattern for an LED show?
shows how directional the light is
Factors that need to be looked at when determining the signal voltage at base of small bipolar amplifier:
source voltage bias resistance input resistance
the load resistance decreases, the series current
stays the same
BJT is applied as a
switch
A Schottky diode is a diode that
switches very fast
a voltage regulator compensates for changes in
temperature input voltage load conditions
silicon diode has voltage to ground of 117V from anode(+). The voltage from ground to cathode is 117.7V, the diode is
the diode is reversed bias
the atomic number of an atom is
the number of protons in the nucleus
the boundary between the p and n type material in a diode is
the pn junction
what diode has a negative resistance region?
the tunnel diode has negative resistance
The base of the NPN transistor is
thin and lightly doped
What is the varactor diode used for?
tuning circuits
a tunnel diode has
tunnel diode has a negative resistance
diode with negative resistance characteristic is needed you would use this diode
varactor diode
what bias is the varactor diode usually
varactor is usually reversed
two types of reverse breakdown in zener diode
zener and avalanche
hFE =
ßDC
