General aviation electricity ch. 2 and ch.3
Ampere
1 blank is the amt of current thru a 1 ohm resistance that has one volt of potential difference applied across it
746 W
1 horsepower is equal to
True
1 horsepower is equal to 3 quarter kilowatt
Work on circuits with power disconnected whenever possible
1 of the best safety rules is to
Resistance
A blank is a material whose elements have an atomic structure that allows free electrons to drift thru if with more or less force applied
Fusible
A blank resistor is a wire-wound resistor made to burn open easily when the power rating is exceeded
False
A decade resistance box is typically used as a potentiometer
Decade box
A device that is used to provide any one resistance with in a wide range of values is a
False
A graph referred to as the volt-ampere characteristic R shows how much resistance exists for different currents
Volt ampere characteristic of R
A graph that shows how much current a resistor allows for different voltages is called the
False
A potentiometer can never be wired as a rheostat
Three terminals
A potentiometer has
True
A resistance can be considered some material whose elements have an atomic structure that allows free electrons to drift through it with more or less force applied
Limit current or produce a voltage drop
A resistor is used to
True
A resistor that is color-coded red, green, red, has a value of 2500 ohms
Zero
A resistor with a single black band around the center of the resistor body has a resistance
True
A rheostat has two terminals and a potentiometer has three terminals
False
A straight line graph shows that a resistor is nonlinear
Linear
A straight-line graph shows that a resistor is
Shock
A sudden involuntary contraction of the muscles, with a feeling of pain, caused by current thru the body is referred to as
True
A thermistor is a thermally sensitive resistor whose resistance value changes with changes in operating temperature
Rheostat
A variable resistance with two terminals that is connected in series with the load
Tolerance
Aging, which is normal resistor heating over a long period of time causes the resistor to exceed its
Tungsten
An example of a nonlinear resistance is the
True
An important safety tip to follow is to keep yourself insulated from earth ground when working on power-lines
An open circuit
As measured with an ohmmeter, infinite ohms means
Surface
Blank mount resistors are constructed by depositing a thick carbon film on a ceramic base
Wire-wind, high wattage resistors
Commercial rheostats are typically
0.001
Concerning electric shock, the threshold of sensation occurs when the current thru the body is only slightly above blank
Derated
For ambient temperatures greater that 70 degrees Celsius, the power rating of a resistor must be
5A
How much current is needed for a 600-W, 120-V toaster
2500 ohms
If a resistor is color coded red blue and orange what is its resistance value
Vary
If the resistance in a circuit is kept the same, but the voltage is varied, the current will blank
Carbon
In electronic equipment, the resistor most commonly used is the
False
Metal-film resistors are made of finely divided carbon or graphite mixed with a powdered insulating material
Metric
Multiple and submultiple values used in electronic applications are based on the blank system of units
False
Note that the resistor itself is very likely to develop a short circuit because of the nature of its construction
Inversely
Ohm's law states that current is blank proportional to resistance
True
Ohm's law states that the amount of current is directly proportional to the voltage and inversely proportional to the resistance
True
One ampere is the amt of current thru a 1 ohm resistance that has one colt of potential difference applied across it
IxV
Power is equal to
True
Power is equal to voltage times current
True
Power is generated by the source of applied voltage and consumed in the resistance
Ohmmeter
Resistance is measured with an
False
Resistors have a relatively short self life and only keep their characteristics for six to eight months
Lower
Resistors with higher resistance values usually have blank wattage ratings
Variable resistors
Rheostats and potentiometers are referred to as
Wire-wound
Since they are generally used for high current applications, blank resistors are available in wattage ratings from 1W up to 100W or more
Resistance
Some material whose elements have an atomic structure that allows free electrons to drift through it with more or less force applied is a
Tolerance
The amt by which the actual resistance can differ from the color coded value is the
False
The amt by which the actual resistance can differ from the color coded value is the positive temperature coefficient
1 ohm
The amt of opposition in a resistance that allows 1 ampere of current with 1 volt applied is
True
The fact is that high/voltage circuits usually do have small values of current in electronic equipment
True
The main function of a resistor is to limit the amt of current or produce a desired drop in voltage
Max working voltage rating
The max allowable voltage that a resistor can safely withstand without internal arcing is called the
True
The max working voltage of a resistor is the max allowable voltage that the resistor can safely withstand without internal arcing
M
The metric system uses what letter 1 million
An open
The most common trouble in resistors is
True
The most common trouble in resistors is an open
Directly
The ohm's law formula stars the V and I are blank proportional for any one value of R
It's physical size
The power of wattage rating of a resistor is determined
Size
The power rating is a property of a resistor that depends on the resistor's
Electric power
The rate at which charge is forced to move by voltage is called
Power
The rate of doing work is
3 digit number printed on the film or body
The resistance value of a chop resistor is determined
False
The two main characteristics of a resistor are its resistance in ohms and its tolerance in mhos
False
The unit of electric power is the joule
Taper of the control
The way resistance varies with shaft rotation in a variable resistor is called the
Watt
The work done in one second by 1 volt of potential difference in moving 1 coulomb of charge is the
Resistance in ohms and power eating in watts
Two major characteristics of a resistor are
Carbon type
Variable resistors can be wire wound
True
Variable resistors can be wire wound or carbon type
False
We pay for electricity in kilowatts
Worn or dirty resistance element
What is indicated when a volume of tone control makes a scratchy noise as the shaft is rotated
Heat
What is produced when current flows in a resistance
Joule
What is the basic practical units of energy
1 volt
What is the potential difference across a 1 ohm resistance that has 1 ampere of current thru it
200W
What is the power in a circuit where the source of 100V produces 2A in a 50 omega R
Fusible
What is the resistor called that is designed to burn open easily when the power rating is exceeded
2
What is the resistor safety factor that allows the resistor to operate without breaking down from excessive heat
Kilowatt-hours
What is the unit commonly used for large amts of electrical energy
Parallel resistance paths
What may cause a much a lower resistance value to be displayed on an ohmmeter when checking resistance in a circuit
Power supply
What piece of equipment provides a variable dc output voltage to electronic circuits under test
Rheostat
What resistive device is generally used to control relatively large values of current in low resistance circuits for ac power applications
Wire wound
What type of resistor is constructed by wrapping resistance wire around an insulating
Metal-film
What type of resistor is formed by spraying a thin film of metal onto a ceramic substrate and the cut in the form of a spiral
Thermistor
What type of resistor is frequently used in electronic circuits in which it is desired to provide temperature control
Wire wound
What type of resistor is typically used as a precision resistor
True
When checking resistance in a circuit, it is important to be sure there are no parallel resistance paths
Almost indefinitely
When not used, resistors generally keep their characteristics
Abscissa
When plotting a graph of current versus voltage, the horizontal axis is referred to as the x axis or as the blank
Less resistance
When the applied voltage is constant, the current is more with
Short
When the current flow in a circuit becomes excessive, a resistor is more likely to
False
Whenever there is current through a resistance, it must have a potential difference across its two ends equal to the IR sum
IR
Whenever there is current thru a resistance, it must have a potential difference across its 2 ends equal to the blank
R=V/I
Which of the following formulas correctly expresses Ohm's law
True
Wire wound resistors are larger and have higher wattage ratings than carbon resistors
True
Zero-ohm resistors are commonly found on printed circuit boards