Download Amateur Radio Technician Class Element 2 Course Presentation

Leveraging Ham Radio for STEM
G7A – G7C
Practical Circuits
Week 2: Ohms Law Review,
Capacitance, Inductance,
Semiconductors, Amplifiers
Ohm’s Law In Practice
• The next series of exercises will put Ohm’s
Law to use to illustrate some principles of
basic electronics.
• As in the previous exercise you will build
the circuits and insert the VOM into the
circuit in the appropriate way to make
current and voltage measurements.
• Throughout the exercise record your data
so that you can compare it to calculations.
Ohm’s Law In Practice
• Build up the illustrated
circuit.
 R1 = 1 k-ohm
 R2 = 1 k-ohm
 R3 = 2.2 k-ohm
 R4 = 300 ohm
• Measure the current
flowing through the
circuit.
A
+
R1
R3
R2
R4
Ohm’s Law In Practice
• Now move the
VOM to the other
side of the circuit
and measure the
current.
• The current should
be the same as the
previous
measurement.
A
+
-
Ohm’s Law In Practice
• Insert the VOM at the
indicated location and
measure the current.
• There should be no
surprise that the current
is the same.
+
A
-
Ohm’s Law In Practice
• Measure the
voltage across R1.
• Using Ohm’s law,
calculate the
voltage drop
across a 1K ohm
resistor at the
current you
measured
• Compare the
result.
V
Ohm’s Law In Practice
• In this next step, you
will insert the VOM in
the circuit at two
places illustrated at
the right as #1 and
#2.
• Record your current
readings for both
places.
• Add the currents and
compare and contrast
to the current
measured entering
the total circuit.
#2
#1
A
A
Ohm’s Law In Practice
• Using the current measured through #1 and the
resistance value of R2, 1k ohms, calculate the
voltage drop across the resistor.
• Likewise do the same with the current measured
through #2 and the resistance value of R3, 2.2k
ohms.
• Compare and contrast these two voltage values
Ohm’s Law In Practice
• Measure the
voltage across the
parallel resistors
and record your
answer.
• Compare and
contrast the
voltage measured
to the voltage drop
calculated.
V
Ohm’s Law In Practice
• In the next step,
insert the VOM into
the circuit as
illustrated, measure
and record the
current.
• Compare and
contrast the current
measured to the total
current measured in a
previous step.
• Were there any
surprises?
A
Ohm’s Law In Practice
• Using the current you
just measured and the
resistance of R4 (330
ohms), calculate what
the voltage drop
across R4 should be.
• Insert the VOM into
the circuit as
illustrated and
measure the voltage.
• Compare and
contrast the
measured and
calculated voltages.
V
Ohm’s Law In Practice
• There is one final
measurement to
complete this portion of
the exercise. Insert the
VOM as indicated.
• Recall the 3 voltages
measured previously;
across R1, R2 and R3, and
across R4.
• Add these three voltages
together and then
compare and contrast
the result with the total
voltage just measured.
V
Ohm’s Law In Practice
• What you observed was:
• The sum of the individual currents entering a node was
equal to the total current leaving a node .
• The sum of the voltage drops was equal to the total voltage
across the circuit.
• This is Kirchhoff’s law and is very useful in the study of
electronic circuits.
• You also noted that Ohm’s law applied throughout the circuit.
The Capacitor
• Capacitance defined
• Physical construction
• Types
• How construction
affects values
• Power ratings
• Capacitor
performance with AC
and DC currents
• Capacitance values
• Numbering system
• Capacitors in circuits
• Series
• Parallel
• Mixed
The Capacitor
The Capacitor
Defined
• A device that stores
energy in electric field.
• Two conductive plates
separated by a non
conductive material.
• Electrons accumulate on
one plate forcing
electrons away from the
other plate leaving a net
positive charge.
• Think of a capacitor as
very small, temporary
storage battery.
The Capacitor
Physical Construction
• Capacitors are rated by:
• Amount of charge that can
be held.
• The voltage handling
capabilities.
• Insulating material
between plates.
Circuit Components
 Low equivalent series resistance is an important characteristic for
capacitors used to filter the DC output of a switching power supply. (G6A01)
Modern switching power supplies
incorporate “crowbar protection” to
provide overvoltage protection.
 Electrolytic capacitors are often used in power-supply circuits to filter
the rectified AC. (G6A02)
 An advantage of ceramic capacitors as compared to other types of
capacitors is comparatively low cost. (G6A03)
Circuit Components
 High capacitance for given volume is an advantage of an
electrolytic capacitor. (G6A04)
Electrolytic
Capacitors
 The effect of lead inductance in a capacitor used at VHF frequencies
and above is that effective capacitance may be reduced because of
the lead inductance. (G6A05)
 The resistance of a carbon resistor will change depending on the
resistor's temperature coefficient rating if the ambient
temperature is increased. (G6A06)
The Capacitor
Ability to Hold a Charge
• Ability to hold a charge depends
on:
• Conductive plate surface
area.
• Space between plates.
• Material between plates.
Charging a Capacitor
Charging a Capacitor
• In the following activity you
will charge a capacitor by
connecting a power source (9
volt battery) to a capacitor.
• You will be using an
electrolytic capacitor, a
capacitor that uses polarity
sensitive insulating material
between the conductive plates
to increase charge capability
in a small physical package.
• Notice the component has
polarity identification + or -.
+
Charging a Capacitor
• Touch the two leads of the capacitor together.
• This short circuits the capacitor to make sure there is no
residual charge left in the capacitor.
• Using your VOM, measure the voltage across the leads of the
capacitor
Charging a Capacitor
• Wire up the illustrated
circuit and charge the
capacitor.
• Power will only have to be
applied for a moment to
fully charge the capacitor.
• Quickly remove the
capacitor from the circuit
and touch the VOM probes
to the capacitor leads to
measure the voltage.
• Carefully observe the
voltage reading over time
until the voltage is at a very
low level (down to zero
volts).
+
Discharging a Capacitor
The Capacitor
Behavior in DC
• When connected to a DC source, the capacitor charges and holds
the charge as long as the DC voltage is applied.
• The capacitor essentially blocks DC current from passing through.
The Capacitor
Behavior in AC
• When AC voltage is applied, during one half of
the cycle the capacitor accepts a charge in one
direction.
• During the next half of the cycle, the capacitor is
discharged then recharged in the reverse
direction.
• During the next half cycle the pattern reverses.
• It acts as if AC current passes through a capacitor
The Capacitor
Behavior
• A capacitor blocks the passage of DC current
• A capacitor passes AC current
The Capacitor
Capacitance Value
• The unit of capacitance is the farad.
• A single farad is a huge amount of capacitance.
• Most electronic devices use capacitors that are a very tiny
fraction of a farad.
• Common capacitance ranges are:
 Micro
10-6
 Nano
 Pico

n
p
10-9
10-12
The Capacitor
Capacitance Value
• Capacitor identification
depends on the capacitor
type.
• Could be color bands,
dots, or numbers.
• Wise to keep capacitors
organized and identified
to prevent a lot of work
trying to re-identify the
values.
Capacitors in Circuits
• Three physical factors
affect capacitance values.
• Plate spacing
• Plate surface area
• Dielectric material
• In series, plates are far
apart making capacitance
less
+
Charged plates
far apart
-
C1C2
CE 
C1  C2
Capacitors in Circuits
• In parallel, the surface area
of the plates add up to be
greater.
• This makes the total
capacitance higher.
+
-
CE  C1  C2
The Inductor
• Inductance defined
• Physical construction
• How construction
affects values
• Inductor performance
with AC and DC
currents
The Inductor
•
•
There are two fundamental principles of electromagnetics:
1. Moving electrons create a magnetic field.
2. Moving or changing magnetic fields cause electrons to
move.
An inductor is a coil of wire through which electrons move,
and energy is stored in the resulting magnetic field.
The Inductor
• Like capacitors,
inductors
temporarily store
energy.
• Unlike capacitors:
• Inductors store
energy in a magnetic
field, not an electric
field.
• When the source of
electrons is removed,
the magnetic field
collapses
immediately.
The Inductor
• Inductors are
simply coils of wire.
• Can be air wound
(just air in the
middle of the coil)
• Can be wound
around a permeable
material (material
that concentrates
magnetic fields)
• Can be wound
around a circular
form (toroid)
The Inductor
• Inductance is measured in Henry(s).
• A Henry is a measure of the intensity of the magnetic field that is
produced.
• Typical inductor values used in electronics are in the range of
millihenry (1/1000 Henry) and microhenry (1/1,000,000 Henry)
The Inductor
• The amount of
inductance is
influenced by a
number of factors:
• Number of coil turns.
• Diameter of coil.
• Spacing between
turns.
• Size of the wire used.
• Type of material
inside the coil.
Circuit Components
 The advantages of using a ferrite core with a toroidal inductor (G6A09):
 Large values of inductance may be obtained
 The magnetic properties of the core may be optimized for a specific range of
frequencies
 Most of the magnetic field is contained in the core
All of these choices are correct.
Circuit Components
 The winding axes of solenoid inductors should be placed at right
angles to minimize their mutual inductance. (G6A10)
 It is important to minimize the mutual inductance between two
inductors to reduce unwanted coupling between circuits. (G6A11)
Circuit Components
 Filter choke is a common name for an inductor used
to help smooth the DC output from the rectifier in a
conventional power supply. (G6A12)
 An effect of inter-turn capacitance in an inductor is
that the inductor may become self resonant at
some frequencies.(G6A13) Capacitor: consists of metal separated
by a layer(s) of a non conductor.
 The peak-inverse-voltage rating of a rectifier is the
maximum voltage the rectifier will handle in the
non-conducting direction. (G6B01)
Non-conducting
region
Notice
Waveforms
Inductor Performance With DC Currents
• When a DC current is applied to an inductor, the
increasing magnetic field opposes the current
flow and the current flow is at a minimum.
• Finally, the magnetic field is at its maximum and
the current flows to maintain the field.
• As soon as the current source is removed, the
magnetic field begins to collapse and creates a
rush of current in the other direction, sometimes
at very high voltage.
Inductor Performance With AC Currents
• When AC current is applied to an inductor,
during the first half of the cycle, the magnetic
field builds as if it were a DC current.
• During the next half of the cycle, the current is
reversed and the magnetic field first has to
decrease the reverse polarity in step with the
changing current.
• These forces can work against each other
resulting in a lower current flow.
The Inductor
• Because the
magnetic field
surrounding an
inductor can cut
across another
inductor in close
proximity, the
changing magnetic
field in one can
cause current to flow
in the other … the
basis of transformers
The Diode
• The semi-conductor phenomena
• Diode performance with AC and DC currents
• Diode types
• General purpose
• LED
• Zenier
The Diode
The semi-conductor phenomena
• Atoms in a metal allow a “sea” of electrons that are relatively free to
move about.
• Semiconducting materials like Silicon and Germanium have fewer
free electrons.
• Impurities added to semiconductor material can either add free
electrons or create an absence of free electrons (holes).
The Diode
The semi-conductor phenomena
• Consider the bar of silicon at the right.
• One side of the bar is doped with negative
material (excess electrons). The cathode.
• The other side is doped with positive
material (excess holes). The anode
• In between is a no man’s land called the P-N
Junction.
The Diode
The semi-conductor phenomena
• Consider now applying a negative voltage
to the anode and positive voltage to the
cathode.
• The electrons are attracted away from the
junction.
• This diode is reverse biased meaning no
current will flow.
The Diode
The semi-conductor phenomena
• Consider now applying a positive voltage to
the anode and a negative voltage to the
cathode.
• The electrons are forced to the junction.
• This diode is forward biased meaning
current will flow.
The Diode
• Set up the illustrated
circuit on the proto
board.
• Note the cathode
(banded end) of the
diode.
• The 330 ohm
resistor in the
circuit is a current
limiting resistor (to
avoid excessive
diode current).
A
330
The Diode
• Use the same circuit, but
reverse the diode.
• Measure and record the
current.
A
The Diode
• Build the illustrated circuit.
• Measure the voltage drop
across the forward biased
diode.
V
The Diode
with AC Current
• If AC is applied to a diode:
• During one half of the cycle the diode is forward biased
and current flows.
• During the other half of the cycle, the diode is reversed
biased and current stops.
• This is the process of rectification, allowing current to flow in
only one direction.
• This is used to convert AC into pulsating DC.
The Diode
with AC Current
Output Pulsed DC Voltage
Diode
conducts
Diode off
Input AC
Voltage
The Light Emitting Diode
• In normal diodes, when electrons combine with
holes current flows and heat is produced.
• With some materials, when electrons combine
with holes, photons of light are emitted, this
forms an LED.
• LEDs are generally used as indicators though
they have the same properties as a regular
diode.
The Light Emitting Diode
• Build the illustrated circuit
on the proto board.
• The longer LED lead is the
anode (positive end).
• Observe the diode
response
• Reverse the LED and
observe what happens.
• The current limiting
resistor not only limits the
current but also controls
LED brightness.
330
Circuit Components
 An LED is forward biased when emitting light. (G6C08)
Array of LEDs and resistors
Circuit Components
 LCDs do not emit light. Therefore, a liquid crystal display requires
ambient or back lighting. (G6C09)
 A computer and transceiver are two devices in an amateur radio
station that might be connected using a USB interface. (G6C10)
The universal serial bus
(USB) has made it simple
to connect your ham
radio to your computer.
Zener Diode
• A Zener diode is
designed through
appropriate doping so
that it conducts at a
predetermined reverse
voltage.
• The diode begins to
conduct and then
maintains that
predetermined voltage
• The over-voltage and
associated current must
be dissipated by the
diode as heat
9V
4.7V
Circuit Components
 The two major ratings that must not be exceeded for silicon-diode
rectifiers are peak inverse voltage; average forward current. (G6B02)
 The approximate junction threshold voltage of a germanium diode is
0.3 volts. (G6B03)
• This is the voltage drop across the diode junction when it is conducting in the
forward direction.
 When two or more diodes are connected in parallel to increase current
handling capacity, the purpose of the resistor connected in series with
each diode is to ensure that one diode doesn't carry most of the
current. (G6B04)
Circuit Components
 The approximate junction threshold voltage of a silicon diode is 0.7
volts. (G6B05)
• This is the voltage drop across the diode junction when it is conducting in the
forward direction
 Lower capacitance is an advantage of using a Schottky diode in an
RF switching circuit as compared to a standard silicon diode. (G6B06)
• It is desirable to have low capacity across the diode junction in higher
frequencies where the capacitive reactance forms a significant path around
the diode when reverse (Back) biased in the non conductive state.
 The stable operating points for a bipolar transistor used as a switch
in a logic circuit are its saturation and cut-off regions. (G6B07)
• Saturation is where the transistor is Base biased for maximum emitter to
collector current flow
• Cut-off is where the transistor base is biased for minimum emitter to collector
current flow
The Transistor
(Electronic Valves)
• How they work, an inside look
• Basic types
• NPN
• PNP
• The basic transistor circuits
• Switch
• Amplifier
The Transistor
collector
base
emitter
The Transistor
collector
e-
N
conducting
P
base
e-
N
emitter
forward bias
e-
The base-emitter current controls the collector-base current
The Transistor
non-conducting
N
P
e-
base
collector
N
emitter
reverse bias
e-
The Transistor
• There are two basic types of
transistors depending of the
arrangement of the material.
• PNP
• NPN
• An easy phrase to help
remember the appropriate
symbol is to look at the arrow.
• PNP – pointing in proudly.
• NPN – not pointing in.
• The only operational difference
is the source polarity.
PNP
NPN
The Transistor Switch
• During the next two activities
you will build a transistor
switch and a transistor
amplifier.
• The pin out of the 2N3904
transistor is indicated here.
E
B
C
The Transistor Switch
• Build the circuit on the
proto board.
• Use hook up wire to
serve as “switches” to
connect the current to
the transistor base.
• What happens when
you first apply power
when the base is left
floating (not
connected)?
330
9-volt
1000
The Transistor Switch
• Make the illustrated
adjustment to the
circuit.
• Connect one end of
some hook-up wire to
the positive side of the
9 volt battery.
• Touch the other end
(supply 9 volts) to the
resistor in the base line
and observe what
happens.
330
1000
The Transistor Switch
• Now replace the
hook-up wire
connection with a
connection to a 1.5
volt battery as shown.
• What happens when
+1.5 volts is applied
to the base?
• What happens when
the battery is
reversed and –1.5
volts is applied to the
base?
330
9V
1.5V
1000
The Transistor Switch
• When does the transistor
start to turn on?
• Build up the illustrated
circuit with the variable
resistor in the base circuit
to find out.
330
9V
1000
Circuit Components
 The cases of some large power transistors must be insulated from ground
to avoid shorting the collector or drain voltage to ground. (G6B08)
Power Transistors
Insulating wafer
 In a MOSFET, the gate is separated from the channel with a thin
insulating layer. (G6B09)
Circuit Components
 The control grid is the element of a triode vacuum tube used to
regulate the flow of electrons between cathode and plate. (G6B10)
H=Heater/Filament; C=Cathode;
S=Screen Grid; P=Plate
Circuit Components
 A Field Effect Transistor is the solid state device most like a
vacuum tube in its general operating characteristics. (G6B11)
• In the construction of a MOSFET the gate is separated from the channel
with a thin insulating layer.
• The Gate is similar to the grid of a tube, it controls current flow.
Circuit Components
 The primary purpose of a screen grid in a vacuum tube is to reduce
grid-to-plate capacitance. (G6B12)
 High discharge current is an advantage of the low internal
resistance of Nickel Cadmium batteries. (G6B13)
 10.5 volts is the minimum allowable discharge voltage for maximum
life of a standard 12 volt lead acid battery. (G6B14)
 It is never acceptable to recharge a carbon-zinc primary cell. (G6B15)
Circuit Components
 A linear voltage regulator, is an example of an analog integrated
circuit.(G6C01)
Schematic symbols and actual linear voltage regulators
Circuit Components
 The term MMIC means Monolithic Microwave Integrated Circuit.
(G6C02)
MMIC
devices
Signal connections
 Low power consumption is an advantage of CMOS integrated circuits
compared to TTL integrated circuits. (G6C03)
• CMOS is the most commonly used digital logic family of integrated circuits.
 The term ROM means Read Only Memory. (G6C04)
Circuit Components
 ROM is characterized as “non-volatile,” meaning the stored
information is maintained even if power is removed. (G6C05)
 Analog is also the term that describes an integrated circuit operational
amplifier. (G6C06)
Schematic symbol
Integrated circuit
• High power consumption is one disadvantage of an incandescent
indicator compared to a LED. (G6C07)
The Integrated Circuit
• The integrated
circuit is a
collection of
components
contained in one
device that
accomplishes a
specific task.
– Acts like a “black-box”
• Circuit Symbol
Protective Components –
Intentional Open Circuits
• Fuses and circuit
breakers are
designed to
interrupt the flow
of current if the
current becomes
uncontrolled.
– Fuses blow – one time
protection.
– Circuit breakers trip – can
be reset and reused.
• Circuit Symbol
Other Circuit Symbols
Putting It All Together in a
Circuit Diagram
Practical Circuits
 A power supply bleeder resistor is a safety feature in that it
discharges the filter capacitors. (G7A01)
R1 and R2 are bleeder resistors
 The output of a rectifier connects to a filter made up of capacitors and
inductors. Capacitors and inductors are used in a power-supply
filter network. (G7A02)
Practical Circuits
 The peak-inverse-voltage across the rectifiers in a full-wave power
bridge supply is equal to the normal peak output voltage of the power
supply. (G7A03)
Notice
Waveforms
Full-Wave Bridge Solid State Power Supply
with pi network filter and resistive load
Practical Circuits
 The peak-inverse-voltage across the rectifiers in a half-wave power
supply is two times the normal output voltage of the power supply.
(G7A04)
 180 degrees is the portion of the AC cycle that is converted to DC by a
half-wave rectifier. (G7A05)
Half-wave rectifier
power supply
Practical Circuits
 360 degrees is the portion of the AC cycle is converted to DC by
a full-wave rectifier. (G7A06)
Full-wave rectifier power supply
 A series of DC pulses at twice the frequency of the AC input
is the output waveform of an unfiltered full-wave rectifier
connected to a resistive load (G7A07)
Practical Circuits
 One advantage of a switched-mode
power supply as compared to a linear
power supply is that high frequency
operation allows the use of smaller
components.(G7A08)
Regulated supply showing outputs
Interior view of a switched-mode
power supply:
A - bridge rectifier
B - Input filter capacitors
C - Transformer
D - output filter coil
E - output filter capacitors
Practical Circuits
 Symbol 1 in figure G7-1 represents a field effect transistor. (G7A09)
Schematic symbol for:
Field Effect Transistor.
Practical Circuits
 Symbol 5 in figure G7-1 represents a Zener diode. (G7A10)
Schematic symbol for:
Zener Diode.
Practical Circuits
Symbol 2 in figure G7-1 represents an NPN junction transistor. (G7A11)
Schematic symbol for:
NPN Junction
Transistor
Practical Circuits
Symbol 6 in Figure G7-1 represents a multiple-winding transformer. (G7A12)
Schematic symbol for:
Multiple-winding
transformer.
Practical Circuits
 Symbol 7 in Figure G7-1 represents a tapped inductor. (G7A13)
Schematic symbol for:
Tapped Inductor.
What is the ability to store energy in an electric field
called? (T5C01)
•
•
•
•
A.
B.
C.
D.
Inductance
Resistance
Tolerance
Capacitance
What is the ability to store energy in an electric field
called? (T5C01)
•
•
•
•
A.
B.
C.
D.
Inductance
Resistance
Tolerance
Capacitance
What is the basic unit of capacitance? (T5C02)
•
•
•
•
A.
B.
C.
D.
The farad
The ohm
The volt
The henry
What is the basic unit of capacitance? (T5C02)
•
•
•
•
A.
B.
C.
D.
The farad
The ohm
The volt
The henry
What is the ability to store energy in a magnetic
field called? (T5C03)
•
•
•
•
A.
B.
C.
D.
Admittance
Capacitance
Resistance
Inductance
What is the ability to store energy in a magnetic
field called? (T5C03)
•
•
•
•
A.
B.
C.
D.
Admittance
Capacitance
Resistance
Inductance
What is the basic unit of inductance? (T5C04)
•
•
•
•
A.
B.
C.
D.
The coulomb
The farad
The henry
The ohm
What is the basic unit of inductance? (T5C04)
•
•
•
•
A.
B.
C.
D.
The coulomb
The farad
The henry
The ohm
What electrical component is used to oppose the
flow of current in a DC circuit? (T6A01)
•
•
•
•
A.
B.
C.
D.
Inductor
Resistor
Voltmeter
Transformer
What electrical component is used to oppose the
flow of current in a DC circuit? (T6A01)
•
•
•
•
A.
B.
C.
D.
Inductor
Resistor
Voltmeter
Transformer
What type of component is often used as an
adjustable volume control? (T6A02)
•
•
•
•
A.
B.
C.
D.
Fixed resistor
Power resistor
Potentiometer
Transformer
What type of component is often used as an
adjustable volume control? (T6A02)
•
•
•
•
A.
B.
C.
D.
Fixed resistor
Power resistor
Potentiometer
Transformer
What electrical parameter is controlled by a
potentiometer? (T6A03)
•
•
•
•
A.
B.
C.
D.
Inductance
Resistance
Capacitance
Field strength
What electrical parameter is controlled by a
potentiometer? (T6A03)
•
•
•
•
A.
B.
C.
D.
Inductance
Resistance
Capacitance
Field strength
What electrical component stores energy in an
electric field? (T6A04)
•
•
•
•
A.
B.
C.
D.
Resistor
Capacitor
Inductor
Diode
What electrical component stores energy in an
electric field? (T6A04)
•
•
•
•
A.
B.
C.
D.
Resistor
Capacitor
Inductor
Diode
What type of electrical component consists of two
or more conductive surfaces separated by an
insulator? (T6A05)
•
•
•
•
A.
B.
C.
D.
Resistor
Potentiometer
Oscillator
Capacitor
What type of electrical component consists of two
or more conductive surfaces separated by an
insulator? (T6A05)
•
•
•
•
A.
B.
C.
D.
Resistor
Potentiometer
Oscillator
Capacitor
What type of electrical component stores energy in
a magnetic field? (T6A06)
•
•
•
•
A.
B.
C.
D.
Resistor
Capacitor
Inductor
Diode
What type of electrical component stores energy in
a magnetic field? (T6A06)
•
•
•
•
A.
B.
C.
D.
Resistor
Capacitor
Inductor
Diode
What electrical component is usually
composed of a coil of wire? (T6A07)
•
•
•
•
A.
B.
C.
D.
Switch
Capacitor
Diode
Inductor
What electrical component is usually composed of
a coil of wire? (T6A07)
•
•
•
•
A.
B.
C.
D.
Switch
Capacitor
Diode
Inductor
What electrical component is used to connect or
disconnect electrical circuits? (T6A08)
•
•
•
•
A.
B.
C.
D.
Zener diode
Switch
Inductor
Variable resistor
What electrical component is used to connect or
disconnect electrical circuits? (T6A08)
•
•
•
•
A.
B.
C.
D.
Zener diode
Switch
Inductor
Variable resistor
What electrical component is used to protect other
circuit components from current overloads?
(T6A09)
•
•
•
•
A.
B.
C.
D.
Fuse
Capacitor
Shield
Inductor
What electrical component is used to protect other
circuit components from current overloads?
(T6A09)
•
•
•
•
A.
B.
C.
D.
Fuse
Capacitor
Shield
Inductor
What class of electronic components is capable of
using a voltage or current signal to control current
flow? (T6B01)
•
•
•
•
A.
B.
C.
D.
Capacitors
Inductors
Resistors
Transistors
What class of electronic components is capable of
using a voltage or current signal to control current
flow? (T6B01)
•
•
•
•
A.
B.
C.
D.
Capacitors
Inductors
Resistors
Transistors
What electronic component allows current to flow in
only one direction? (T6B02)
•
•
•
•
A.
B.
C.
D.
Resistor
Fuse
Diode
Driven element
What electronic component allows current to flow in
only one direction? (T6B02)
•
•
•
•
A.
B.
C.
D.
Resistor
Fuse
Diode
Driven element
Which of these components can be used as an
electronic switch or amplifier? (T6B03)
•
•
•
•
A.
B.
C.
D.
Oscillator
Potentiometer
Transistor
Voltmeter
Which of these components can be used as an
electronic switch or amplifier? (T6B03)
•
•
•
•
A.
B.
C.
D.
Oscillator
Potentiometer
Transistor
Voltmeter
Which of these components is made of three layers
of semiconductor material? (T6B04)
•
•
•
•
A.
B.
C.
D.
Alternator
Bipolar junction transistor
Triode
Pentagrid converter
Which of these components is made of three layers
of semiconductor material? (T6B04)
•
•
•
•
A.
B.
C.
D.
Alternator
Bipolar junction transistor
Triode
Pentagrid converter
Which of the following electronic components can
amplify signals? (T6B05)
•
•
•
•
A.
B.
C.
D.
Transistor
Variable resistor
Electrolytic capacitor
Multi-cell battery
Which of the following electronic components can
amplify signals? (T6B05)
•
•
•
•
A.
B.
C.
D.
Transistor
Variable resistor
Electrolytic capacitor
Multi-cell battery
How is a semiconductor diode’s cathode lead
usually identified? (T6B06)
•
•
•
•
A.
B.
C.
D.
With the word “cathode”
With a stripe
With the letter “C”
All of these choices are correct
How is a semiconductor diode’s cathode lead
usually identified? (T6B06)
•
•
•
•
A.
B.
C.
D.
With the word “cathode”
With a stripe
With the letter “C”
All of these choices are correct
What does the abbreviation “LED” stand for?
(T6B07)
•
•
•
•
A.
B.
C.
D.
Low Emission Diode
Light Emitting Diode
Liquid Emission Detector
Long Echo Delay
What does the abbreviation “LED” stand for?
(T6B07)
•
•
•
•
A.
B.
C.
D.
Low Emission Diode
Light Emitting Diode
Liquid Emission Detector
Long Echo Delay
What does the abbreviation “FET” stand for?
(T6B08)
•
•
•
•
A.
B.
C.
D.
Field Effect Transistor
Fast Electron Transistor
Free Electron Transition
Field Emission Thickness
What does the abbreviation “FET” stand for?
(T6B08)
•
•
•
•
A.
B.
C.
D.
Field Effect Transistor
Fast Electron Transistor
Free Electron Transition
Field Emission Thickness
What are the names of the two electrodes of a
diode? (T6B09)
•
•
•
•
A.
B.
C.
D.
Plus and minus
Source and drain
Anode and cathode
Gate and base
What are the names of the two electrodes of a
diode? (T6B09)
•
•
•
•
A.
B.
C.
D.
Plus and minus
Source and drain
Anode and cathode
Gate and base
Which semiconductor component has an
emitter electrode? (T6B10)
•
•
•
•
A.
B.
C.
D.
Bipolar transistor
Field effect transistor
Silicon diode
Bridge rectifier
Which semiconductor component has an
emitter electrode? (T6B10)
•
•
•
•
A.
B.
C.
D.
Bipolar transistor
Field effect transistor
Silicon diode
Bridge rectifier
Which semiconductor component has a gate
electrode? (T6B11)
•
•
•
•
A.
B.
C.
D.
Bipolar transistor
Field effect transistor
Silicon diode
Bridge rectifier
Which semiconductor component has a gate
electrode? (T6B11)
•
•
•
•
A.
B.
C.
D.
Bipolar transistor
Field effect transistor
Silicon diode
Bridge rectifier
What is the term that describes a transistor’s ability
to amplify a signal? (T6B12)
•
•
•
•
A.
B.
C.
D.
Gain
Forward resistance
Forward voltage drop
On resistance
What is the term that describes a transistor’s ability
to amplify a signal? (T6B12)
•
•
•
•
A.
B.
C.
D.
Gain
Forward resistance
Forward voltage drop
On resistance
What is the name for standardized representations
of components in an electrical wiring diagram?
(T6C01)
•
•
•
•
A.
B.
C.
D.
Electrical depictions
Grey sketch
Schematic symbols
Component callouts
What is the name for standardized representations
of components in an electrical wiring diagram?
(T6C01)
•
•
•
•
A.
B.
C.
D.
Electrical depictions
Grey sketch
Schematic symbols
Component callouts
Which of the following is accurately represented in
electrical circuit schematic diagrams? (T6C13)
•
•
•
•
A.
B.
C.
D.
Wire lengths
Physical appearance of components
The way components are interconnected
All of these choices are correct
Which of the following is accurately represented in
electrical circuit schematic diagrams? (T6C13)
•
•
•
•
A.
B.
C.
D.
Wire lengths
Physical appearance of components
The way components are interconnected
All of these choices are correct
Which of the following devices or circuits changes
an alternating current into a varying direct current
signal? (T6D01)
•
•
•
•
A.
B.
C.
D.
Transformer
Rectifier
Amplifier
Reflector
Which of the following devices or circuits changes
an alternating current into a varying direct current
signal? (T6D01)
•
•
•
•
A.
B.
C.
D.
Transformer
Rectifier
Amplifier
Reflector
Which best describes a relay? (T6D02)
•
•
•
•
A.
B.
C.
D.
A switch controlled by an electromagnet
A current controlled amplifier
An optical sensor
A pass transistor
Which best describes a relay? (T6D02)
•
•
•
•
A.
B.
C.
D.
A switch controlled by an electromagnet
A current controlled amplifier
An optical sensor
A pass transistor
Which of the following can be used to display signal
strength on a numeric scale? (T6D04)
•
•
•
•
A.
B.
C.
D.
Potentiometer
Transistor
Meter
Relay
Which of the following can be used to display signal
strength on a numeric scale? (T6D04)
•
•
•
•
A.
B.
C.
D.
Potentiometer
Transistor
Meter
Relay
What component is commonly used to change
120V AC house current to a lower AC voltage for
other uses? (T6D06)
•
•
•
•
A.
B.
C.
D.
Variable capacitor
Transformer
Transistor
Diode
What component is commonly used to change
120V AC house current to a lower AC voltage for
other uses? (T6D06)
•
•
•
•
A.
B.
C.
D.
Variable capacitor
Transformer
Transistor
Diode
Which of the following is commonly used as a
visual indicator? (T6D07)
•
•
•
•
A.
B.
C.
D.
LED
FET
Zener diode
Bipolar transistor
Which of the following is commonly used as a
visual indicator? (T6D07)
•
•
•
•
A.
B.
C.
D.
LED
FET
Zener diode
Bipolar transistor
Which of the following is used together with an
inductor to make a tuned circuit? (T6D08)
•
•
•
•
A.
B.
C.
D.
Resistor
Zener diode
Potentiometer
Capacitor
Which of the following is used together with an
inductor to make a tuned circuit? (T6D08)
•
•
•
•
A.
B.
C.
D.
Resistor
Zener diode
Potentiometer
Capacitor
What is the name of the device that combines
several semiconductors and other components into
one package? (T6D09)
•
•
•
•
A.
B.
C.
D.
Transducer
Multi-pole relay
Integrated circuit
Transformer
What is the name of the device that combines
several semiconductors and other components into
one package? (T6D09)
•
•
•
•
A.
B.
C.
D.
Transducer
Multi-pole relay
Integrated circuit
Transformer
What is the purpose of a fuse in an electrical
circuit? (T0A04)
•
•
•
•
A.
B.
C.
D.
To prevent power supply ripple from damaging a circuit
To interrupt power in case of overload
To limit current to prevent shocks
All of these choices are correct
What is the purpose of a fuse in an electrical
circuit? (T0A04)
•
•
•
•
A.
B.
C.
D.
To prevent power supply ripple from damaging a circuit
To interrupt power in case of overload
To limit current to prevent shocks
All of these choices are correct
Why is it unwise to install a 20-ampere fuse in the
place of a 5 ampere fuse? (T0A05)
• A. The larger fuse would be likely to blow because it is rated for higher
current
• B. The power supply ripple would greatly increase
• C. Excessive current could cause a fire
• D. All of these choices are correct
Why is it unwise to install a 20-ampere fuse in the
place of a 5 ampere fuse? (T0A05)
• A. The larger fuse would be likely to blow because it is rated for higher
current
• B. The power supply ripple would greatly increase
• C. Excessive current could cause a fire
• D. All of these choices are correct
• An amplifier… with a FET (Field Effect Transistor)
Amplifier
Vcc +
1k
.1uF
Input
.1uF
Output
D
G
MPF 102
S
165