Review Exercise 4-1
Part I:
Fill in the blanks or answer the question
n
The outer shell of an atom is called the __________________ shell.
valence
n
The flow of electrons is called _____________________
current
n
The charge of 6.14 x1018 electrons is called a
____________________ coulomb
n
The unit of measurement for current is the __________________
ampere
n
__________________ is the force that moves electrons in a circuit
voltage
n
__________________ is a general name for materials with high
resistance Insulators
n
__________________ is a general name for materials with low
resistance conductors
n
Write the symbol or letter for the following items in the space
provided
|
Item |
Symbol |
|
10-3 |
m |
|
10-6 |
m |
|
103 |
K |
|
106 |
M |
n
One amp is the amount of current that flows in a conductor when one
____________ of charge
moves past a
point in one second.
coulomb
n
List the 2 basic types of cells below
Ø
________________________
primary
Ø
________________________
secondary
n
Cells that can be recharged are called
________________________________ cells
secondary
n
What is the name of the instrument used to measure
Ø
Resistance: _________________
Ohmmeter
Ø
Current: ________________
Ammeter
Ø
Voltage: ___________________________________
Voltmeter
n
A resistor's ______________________ is the amount that it may vary
and still be acceptable.
tolerance
n
For each of the following, indicate whether the instrument is
connected in series with the item being
measure or
in parallel (your answer should be either series or parallel).
Ø
Resistance: _________________
Parallel
Ø
Current: ____________________
Series
Ø
Voltage: ___________________________________
Parallel
n
A way to measure current that does not require opening the circuit is
to use a resistor of known
value in the
circuit. Such a resistor is called a (an)
_____________________________________
ammeter shunt.
n
The testing for an open, closed, or short circuit is called a
_____________________ check.
continuity
n
List the 2 types of ground discussed in the text.
Ø
__________________________
earth
Ø
__________________________
electrical
n
_________________ produces the energy to dislodge electrons from
their orbit.
voltage
n
Resistors are either __________________ or __________________
fixed, variable
n
Variable resistors used to control voltage are called
________________ potentiometers
n
Variable resistors used to control current are called
_________________ rheostats
n
The relationship of current, voltage, and resistance is given by
_______________ law.
Ohm's
n
Current that flows in one direction and then the other is called
___________________________
alternating current
n
Current that flows in one direction only is called
___________________________ direct
current.
n
The ______________________ marking on a resistor is used to indicate
the amount that a
resistor's value may vary and still be acceptable.
tolerance
n
The total current flowing into a junction is equal to the sum of the
current flowing out of the
junction is a statement of ___________________________ current law.
Kirchoff's
n
The basic unit of power is the ____________________________
watt
n
What is the current in amps if 15 coulombs of current flows past a
point in an electric circuit in 5
seconds?
3 coulombs/second = 3 amps
n
Given 4 resistors, each with a resistance of 2 ohm, that are
connected in parallel. What is the
equivalent
resistance, RE?
1/RE = 1/2 + 1/2 + 1/2 + 1/2 = 2
RE = 1/2
n
Given 4 resistors, each with a resistance of 2 ohm, that are
connected in series. What is the
equivalent
resistance, RE?
RE = 2 + 2 + 2 + 2 = 8 ohms
n
Given the following circuit. The battery supplies 12 volts. The total
voltage drop across the 3
resistors is
_____________ 12 volts (Kirchoff's
energy conservation law)
n
Assume that you have batteries each rated at 9 volts and 6 A/h. Draw
a circuit below that will result
in 18 volts and 12
A/h. Do not show a load.
n
How much current is used by a 100-watt, 120 volt light bulb?
P = IE
100 = I(120) gives I = 100/120 = 0.83 amp
n
Given that a current of 0.5 amp flows through a 20 ohm resistor, how
much power is dissipated by
the
resistor?
V = IR = 0.5x20 = 10 volts
P = VI = 10x0.5 = 5 watts
n
A resistor's ______________________ is the amount that it may vary
and still be acceptable.
tolerance
n
What is the current in amps if 15 coulombs of current flows past a
point in an electric circuit in 5
seconds?
3 coulombs/second = 3 amps
n
A ________________________ consists of invisible lines of force that
surround a magnet.
magnetic field
n
The invisible lines of force above are referred to as _________________
lines
flux
n
_________________________ is the effect a magnet has on an object without
physical
contact.
Magnetic induction
n
A ________________ is an electromechanical switch that opens and closes with
an
electromagnetic coil.
relay
n
The strength of an electromagnet is directly proportional to:
Ø
____________________________________
Number of turns in the coil
Ø
____________________________________
Amount of current flowing
through the coil.
n
____________________ law states that the inducted voltage is directly
proportional
to the rate
at which the conductor cuts the magnetic lines of force.
Faraday's
n
For electromagnetic induction to occur, either the magnetic field or the
conductor must
move. The
voltage produced in the conductor is called ________________ voltage.
induced
n
In an AC generator the rotating loop is called a (an)
__________________________.
armature
n
A DC generator converts
mechanical energy to electrical energy, similar to an AC generator
except that
it converts the AC voltage to DC voltage. It does this with a device called
a
_________________
commutator.
n
An AC generator converts mechanical energy
to electrical energy by utilizing the principle
of
______________ induction.
electromagnetic
n
The letter symbol _____________ represents inductance.
L
n
The unit of inductance is the _______________.
Henry
n
The letter symbol ___________represents the unit of inductance.
H
n
Draw the schematic symbol a fixed inductor in the space below.
n
Draw the schematic symbol for a variable inductor below.
Same as above with an arrow though it pointed up and to the right.
n
Given three inductors with inductances L1, L2, and L3.
Ø
If conducted in series, the total inductance LT =
L1 + L2 + L3.
Ø
If conducted in parallel, the total inductance LT =
L1L2L3/(L2L3
+ L1L3 + L1L2)
n
An LR ______________________________ is the time required for current
through
a conductor
to increase to 63.2% or decrease to 36.8% of the maximum current.
time constant
n
Inductance is a measure of the resistance to a change in
_______________ current
n
______________ are devices that store energy in a magnetic field.
Inductors
n
List the equation used to find the time constant, t, for an RL circuit.
t = L/R
L = inductance in henries, R is resistance in ohms
n
An induced emf in any circuit is always in a direction to oppose the effect
that produced it.
This is a
statement of ______________________ law.
Lenz's
n
The letter symbol ____________represents capacitance.
C
n
The unit of capacitance is the ____________Farad
n
The letter symbol ____________ represents capacitance.
F
n
Draw the schematic symbol for a fixed capacitor in the space below.
n
Draw the schematic symbol for a variable capacitor in the space
below.
Same as above with an arrow though it pointed up and to the right.
n
Given three capacitors with capacitances C1, C2, and C3
Ø
If conducted in series, the total capacitance CT =
C1C2C3/(C2C3
+ C1C3 + C1C2)
Ø
If conducted in parallel, the total capacitance CT =
C1
+ C2 + C3.
n
Four factors that affect the capacitance of a capacitor are
Ø
____________________________________
Area of the plate
Ø
____________________________________
Distance between the plates
Ø
____________________________________
Type of dielectric material
Ø
____________________________________
Temperature
n
An RC __________________________ reflects the relationship between time,
resistance,
and capacitance.
time constant
n
Each time an AC generator moves through one complete revolution, it
is said to complete one
_______________.
cycle
n
The rotating loop of wire in an AC generator is called the
____________________________.
armature
n
The two halves of an AC cycle are referred to as __________________.
alterations
n
One cycle per second is defined as a ____________________.
hertz
n
The most basic and widely used of all the AC waveforms is the
__________________________
sinusoidal
waveform
n
The _____________________________ of a sine wave is the absolute
value of the point on the
waveform
with the greatest amplitude.
peak value
n
The ___________________________ value refers to the vertical distance
between the two
peaks. It
can be found by adding the absolute value of each peak.
peak-to-peak
n
The _______________________ of alternating current is the amount that
produces the same
degree of
heat in a given resistance as an equal amount of direct current.
effective value
n
The term rms value is often used. rms stands for
________________________ root mean
square
n
A current sine wave has a peak value of 10 amp. What is its effective
value?
Irms =
.707 I = 7.07 A
n
What is the period of a sine wave that has a frequency of 100 hertz?
t = 1/f =
1/100 = 0.01 seconds
n
A very versatile piece of equipment for working on electronic
equipment and circuits is the
__________________________. It provides a visual display of what is
occurring in the circuit,
such a the
frequency and duration of the signal and pulse relationships.
oscilloscope
n
CRT stands for _____________________________________.
cathode ray tube
n
A basic AC circuit consists of the following 3 components
Ø
_______________________source
Ø
______________________conductors
Ø
_____________________________
resistive load
n
When an AC voltage is applied to the resistive load, the AC current's
amplitude and direction vary
in the same
manner as those of the applied load. They are said to be
______________________
in phase
n
Given an AC circuit that has an effective voltage of 120 volts
applied across 2 parallel resistors,
R1
and R2. R1 = 470 ohms and R2 = 1000 ohms.
What is the current flowing through R2?
In a
parallel circuit,
VT
= VR1 = VR2 = 120 volts
IR2
= = VR2/R2 = 120/1000 = 0.0120 A or 12 mA
n
AC current flowing in a conductor causes a magnetic field to expand
and collapse as the current
increases and decreases in
value. This is the principle upon which the _____________________
meter is based.
clamp on
n
A DC meter can be adapted to measure an AC signal by converting the
AC voltage to a DC voltage
using a
_________________________. answer is not capacitor
rectifier
n
The gain of an amplifier may be measured in
Ø
_______________________voltage
Ø
_______________________current
Ø
______________________power
n
Name three common types of distortion
Ø
__________________________frequency
Ø
__________________________phase
Ø
__________________________amplitude
n
Name the two basic classifications of oscillator circuits.
Ø
______________________________LC
Ø
________________________
RC
n
What is the primary function of an LC tank circuit?
To generate a high frequency AC signal
Part II:
Circle the correct answer
n
An amplifier state with an input of 0.1 volt and an output of 2 volt would
have a gain of
a. 5
b. 10
c. 20 answer
d. 0.2
n
What are the frequency determining components in an LC oscillator circuit?
a. transistor &
capacitor b.
resistor & capacitor c.
resistor & coil d.
capacitor &coil
answer
n
The symbol for impedance is
a. E
b. I c. R
d. Z
answer
n
Impedance is measured in
a. volts
b. ohms answer
c. amps
d. watts
n
Which of the amplifier classes listed below would never be used for audio
reproduction?
a. class A
b. class B
c. class AB1
d. class AB2
e. class C
answer