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73 Cards in this Set
- Front
- Back
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What is a solid-state device?
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An electronic device that operates by virtue of the movement of electrons within a solid piece of
semiconductor material |
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Define the term negative temperature coefficient.
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It is the decrease in a semiconductor’s resistance as temperature rises.
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Name three of the largest users of semiconductor devices.
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Space systems, computers, and data processing equipment.
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State one requirement of an electron tube, which does not exist for semiconductors, that makes the
tube less efficient than the semiconductor. |
The electron tube requires filament or heater voltage, whereas the semiconductor device does not;
consequently, no power input is spent by the semiconductor for conduction. |
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What is the outer shell of an atom called?
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The valence shell.
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What term is used to describe the definite discrete amounts of energy required to move an electron
from a low shell to a higher shell? |
Quanta.
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What is the main difference in the energy arrangement between an isolated atom and the atom in a
solid? |
The energy levels of an atom in a solid group together to form energy bands, whereas the isolated
atom does not. |
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What determines, in terms of energy bands, whether a substance is a good insulator,
semiconductor, or conductor? |
The width of the forbidden band.
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What determines the chemical activity of an atom?
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The number of electrons in the valence shell.
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What is the term used to describe the sharing of valence electrons between two or more atoms?
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Covalent bonding.
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Name the two types of current flow in a semiconductor.
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Electron flow and hole flow.
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What is the name given to a piece of pure semiconductor material that has an equal number of
electrons and holes? |
Intrinsic.
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What is the name given to a doped germanium crystal with an excess of free holes?
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P-type crystal.
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What are the majority carriers in an N-type semiconductor?
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Electrons.
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What is the purpose of a PN junction diode?
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To convert alternating current into direct current
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In reference to the schematic symbol for a diode, do electrons flow toward or away from the
arrow? |
Toward the arrow.
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What type of PN diode is formed by using a fine metal wire and a section of N-type semiconductor
material? |
Point-contact.
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What are the majority carriers in a P-type semiconductor?
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Holes.
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Conduction in which type of semiconductor material is similar to conduction in a copper wire?
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N-type material.
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What is the name of the area in a PN junction that has a shortage of electrons and holes?
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Depletion region.
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In order to reverse bias in a PN junction, what terminal of a battery is connected to the P
material? |
Negative.
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What type of bias opposes the PN junction barrier?
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Forward.
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What is a load?
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Any device that draws current
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What is the output of a half-wave rectifier?
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A pulsating dc voltage.
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What type of rectifier is constructed by sandwiching a section of semiconductor material between
two metal plates? |
Metallic rectifier.
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What type of bias makes a diode act as a closed switch?
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Forward bias.
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What is used to show how diode parameters vary over a full operating range?
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A characteristic curve.
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What is meant by diode ratings?
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They are the limiting values of operating conditions outside which operations could cause diode
damage. |
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What does the letter "N" indicate in the semiconductor identification system?
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A semiconductor.
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What type of diode has orange, blue, and gray bands?
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1N368.
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What is the greatest threat to a diode?
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Heat.
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When checking a diode with an ohmmeter, what is indicated by two high resistance
measurements? |
The diode is open or has a high-forward resistance.
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What is the name given to the semiconductor device that has three or more elements?
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Transistor
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What electronic function made the transistor famous?
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Amplification.
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In which direction does the arrow point on an NPN transistor?
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Outward.
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What was the name of the very first transistor?
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Point-contact.
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What is one of the most important parts of any transistor manufacturing process?
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Quality control.
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To properly bias an NPN transistor, what polarity voltage is applied to the collector, and what is its
relationship to the base voltage? |
Positive, more positive.
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Why is conduction through the forward-biased junction of an NPN transistor primarily in one
direction, namely from the emitter to base? |
Because the N material on one side of the forward-biased junction is more heavily doped than the
P-material. |
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In the NPN transistor, what section is made very thin compared with the other two sections?
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The P or base section.
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What percentage of current in an NPN transistor reaches the collector?
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98 percent.
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What are the majority current carriers in a PNP transistor?
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Holes.
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What is the relationship between the polarity of the voltage applied to the PNP transistor and that
applied to the NPN transistor? |
The polarity of voltage applied to the PNP transistor is opposite of that applied to the NPN
transistor |
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What is the letter designation for base current?
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I B.
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Name the two current loops in a transistor.
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The base current loop and the collector current loop
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What is the name of the device that provides an increase in current, voltage, or power of a signal
without appreciably altering the original signal? |
Amplifier.
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Besides eliminating the emitter-base battery, what other advantages can different biasing methods
offer? |
Compensation for slight variations in transistor characteristics and changes in transistor
conduction because of temperature variations. |
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In the basic transistor amplifier discussed earlier, what is the relationship between the polarity of the
input and output signals? |
The signals are opposite in polarity or 180 degrees out of phase with each other.
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What is the primary difference between the NPN and PNP amplifiers?
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The polarity of the source voltage.
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Which biasing method is the most unstable?
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Base current bias or fixed bias
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What type of bias is used where only moderate changes in ambient temperature are expected?
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Self-bias.
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When is degeneration tolerable in an amplifier?
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When it is necessary to prevent amplitude distortion
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What is the most widely used combination-bias system?
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The voltage-divider type.
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What amplifier class of operation allows collector current to flow during the complete cycle of the
input? |
Class A.
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What is the name of the term used to describe the condition in a transistor when the emitter-base
junction has zero bias or is reverse biased and there is no collector current? |
Cutoff.
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What two primary items determine the class of operation of an amplifier?
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The amount of bias and the amplitude of the input signal.
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What amplifier class of operation is the most inefficient but has the least distortion?
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Class A.
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What are the three transistor configurations?
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Common emitter (CE), common base (CB), and common collector (CC).
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Which transistor configuration provides a phase reversal between the input and output signals?
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Common emitter.
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What is the input current in the common-emitter circuit?
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Base current (I B).
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What is the current gain in a common-base circuit called?
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Alpha ().
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Which transistor configuration has a current gain of less than 1?
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Common base.
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What is the output current in the common-collector circuit?
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IE.
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Which transistor configuration has the highest input resistance?
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Common collector.
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List three items of information normally included in the general description section of a
specification sheet for a transistor. |
The kind of transistor, the transistor's common applications, and mechanical data.
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What does the number "2" (before the letter "N") indicate in the JAN marking scheme?
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The number of junctions in the device, which in this case indicates a transistor.
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What is the greatest danger to a transistor?
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Heat.
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What method for checking transistors is cumbersome when more than one transistor is bad in a
circuit? |
The substitution method.
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What safety precaution must be taken before replacing a transistor?
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The power must be removed from the circuit.
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How is the collector lead identified on an oval-shaped transistor?
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By the wide space between the collector lead and the other two leads (emitter and base).
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What are two transistor tests that can be done with an ohmmeter?
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Gain and junction resistance.
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When you are testing the gain of an audio-frequency transistor with an ohmmeter, what is
indicated by a 10-to-1 resistance ratio? |
Normal gain.
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When you are using an ohmmeter to test a transistor for leakage, what is indicated by a low, but
not shorted, reverse resistance reading? |
A leaking transistor
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