Chapter 3-5 Basic Electonics
The north magnetic pole of a compass needle is attracted to the _____ magnetic pole of the earth
South
Insulators are the only materials that can hold _______ stationary
Static
If an object is placed in the field of a strong electromagnet connected to an AC line, the object will be _______
Demagnetized
Lodestone is a name for a naturally occurring magnetic material that is also called _________
Leading stones
To locate the north pole of an electromagnet, use the _____-hand rule
Left
What is indicated by the 4th color band on a resistor?
Multiplier band
How many color bands are used on resistors that have a tolerance of +_20 percent?
3
The strength of ab electromagnet is primarily proportional to its _________
Ampere-turns
Static electricity refers to electrons that ______ moving
Aren't
What type of fixed resistor is made from a compound of carbon graphite and resin bonding material?
Carbon resistor
The angular difference between true north and magnetic north is known as the angle of _________
Declination
In the english system of measure, magnetic strength is measured in terms of ______
Flux density
The measure of a materials ability to be magnetized is called ________
Flux or mmf
If a thundercloud has a positive charge, the current in the lightening bolt will flow from the _______________
Ground to cloud
Man-made permanent magnets retain their magnetism _____ than other natural magnets
Longer
The shock that results from walking across a carpet and touching a doorknob is an example of a(n) _______ static charge
Nuisance
What is another term for a variable resistor?
Potentiometer
The amount of magnetism left in a material after the magnetizing force has stopped is called _______
Residual
The measure of a materials resistance to magnetism is known as __________
Resistance
A variable resistor with 3 terminals is called a _______
Rheostat
When a magnetic materials molecules are all lined up, and increases in current flow no longer cause increase in magnetic field strength, the material has reached __________
Saturation
Selenium is a(n)
Semiconductor
The static charge sometimes used during spray painting is an example of a(n)______ static charge
Useful
A resistor whose values can be varied over a range of values is called a _______ resistor
Variable
Resistors functioning as _______ are used in applications involving field-effect transistors (FETs) and multi-range voltmeter circuits.
Voltage dividers
What type of fixed resistor is made by winding a piece of resistive wire around a ceramic core?
Wire wound resistor
What type of resistors are generally used when a high power rating is needed?
Wire wound resistors
What type of fixed resistor is made by applying a film of carbon to a ceramic rod?
carbon film resistor
Magnetic lines of force are referred to as ________
flux
In the english system, the total force producing a magnetic field is the _______
magnetomotive force
The________of a resistor indicates the plus and minus limits of a resistors ohmic value
tolerance
A basic law of magnetism states that unlike poles _____ and like poles _______
Attract and repel
The regions formed in the molecular structure of magnetic metals are sometimes called magnetic ___________
Domains/molecules
What type of magnet depends on flowing current to produce a magnetic field?
Electromagnets
Magnetism can be explained in terms of _________ spin patterns
Electron
The 3 substances that form natural magnets are
Ferromagnetic, Paramagnetic, and Diamagnetic
The precipitator uses a high-voltage DC power supply to provide a set of wires with a positive charge and a set of plates with a _______ charge
Negative
Within a lightning bolt, current flows ______
Negative to positive
Bringing a charged test object near the ball of a charged electroscope causes the leaves to move closer together. This indicates that the test object charge is the_______ polarity as the electroscope charge.
Opposite
What type of resistors can only have one ohmic value?
Fixed
What color used as the multiplier band means to divide the combined first two number by 10?
Gold
Electrostatic charges occur on _______
Insulator materials
If a permanent magnet is cut into pieces, each piece ________ a separate magnet
Is
A lightning protection device that is grounded at one end is called a(n)___________
Lightning rod
In a clothes dryer, the greatest static charges generally are built up on _______ fabrics
Man-made
What type of fixed resistor is made by applying a film of metal to a ceramic rod in a vaccum?
Metal film resistor
What type of fixed resistor is made by combining metal with glass and then applying it to a ceramic base as a thick film?
Metal glaze resistor
What type of resistor operates by moving the wiper arm with a screw of some number of turns?
Multi turn
What type of magnets do not require any power or force to maintain their field?
Permanent magnets
The semiconductor material used as a coating on copy machine drums is __________
Selenium