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formula for finding electrical power which relates Watts(P), Volts(V) and Amperes(I)
P=VxI
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current is measured in?
amps with a ammeter
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Law of electric power
calculates the amount of power consumed by an electric or electronic device
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ohm's law
the relationship between electric pressure, current strength, and resistance in any circuit.
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electrical power is?
the amount of energy consumed by an electric device. It is measured with an electric meter in WATTS
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electric current is?
the flow of electric charge through a conducting material. it is measured with an Ammeter in Ampere
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1 Ampere is equal to
the flow of 1 coulomb of electricity past a given point per second
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Voltage is?
the force that affects the rate at which electricity flows through a conductor. it is measured with a Voltmeter in Volts
is the unit used to mesure elctrical pressure
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Resistance is?
the opposition of a material to the flow of electricity through it. Measured with an Ohmmeter in OHMs.
-
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frequency is?
the number of times that alternating current (AC) changes direction per second. Measured in Hertz(HZ)
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A battery
stores electric charge and can furnish an electric current
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a Capacitor
stores electric charge temporarily
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ground
an extremely large reservoir of electrons that can supply or accept electrons as needed
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Rectifier
changes alternating current(AC) to direct current(DC)
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Resistor
supplies a resistance to a circuit
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Transformer
can increase (step up) or decrease (step down) the voltage in a circuit
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Transistor
controls the flow of electric current without the use of a vacuum (is a device that amplifies an electronic signal)
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a wire that is covered in black insulation is?
the hot or live wire. if more than one hot wire is used then red and blue can be used
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Neutral wire is covered with what colored insulator?
white or gray
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the grounding wire uses what color insulator?
it is left bare, wrapped in paper or in green insulator
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Conductivity refers to?
the ability of a given material to carry an electric charge
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a Rheostat does what?
it changes the resistance in a circuit
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alternating current supplied to homes ordinarily has a frequency of how many Hertz(HZ)?
60 hertz
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in most homes the items that used electricity are connected in?
parallel circuits
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parellel circuits work how?
has two or more separate branches for the current to flow. with this kin of circuit, if one electrical item fails, the current has alternate paths to follow and its flow to other items is not interrupted.
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series circuit works how?
it only has a single branch for the current to flow. so if it fails the flow of current to all other items is blocked.
-
contain solid-state semiconductor diodes that conduct electricity in only one direction
rectifier
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the flow of electric charge in a a conductor between two point having a difference in potential is called?
Current
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one HZ equals what?
one complete cylce (or two complet alternationsof direction) per second.
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ampere is a measure of the ?
strength of an electrical current
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Watts is calculated by?
multiplying Vots times Amperes
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storage batteries are used on?
cars, trucks and other vehicles. the negative post is thinner that the positive
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Capacity is a measure of how much current a wire can?
carry
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short circuit is when?
an exposed wire carrying current touches anotehr wire or ground metal. the current flos through the point of contact, creating a side circuit and bypassong its intended path.
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circuit overload
when things draw more amperes than a circuit is designed to handle.
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circuit overload and short circuit will?
trip the circut breaker, instantly stopping the flow of current
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Parallel Circuit
has different parts on separate branches. One branch can be switched off without affecting the flow of current to other branches
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a charge of X coulombs moves through a circuit in X seconds. the current in the circuit can be found by?
dividing the number of coulombs by the amount of time
- Coulombs = Amperes
- seconds
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three elements of a transistor are?
collector , base, emitter
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Insulators are materials that?
do not allow electrons to flow freely, thus preventing the formation of electric current. (rubber, wood, plastic and air)
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the watt is a measure of electrical
power
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the hertz is a measure of elctrical
frequency
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electron current is defined
as the direct flow of electrons
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electric current flows from
negatice to positive potential
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resistance is said to vary directly with the
length of the wire. (the longer a wire the more resistance it has)
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black =0
Brown =1
red =2
orange
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yellow =4
green =5
blue =6
violet =7
gray =8
white =9
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the fourth stripe represents
the resistor tolerance
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fourth silver is equal to?
Gold is equal to?
missing fourth stripe means its equal to?
+ or - 10 %
+ or - 5 %
+ or - 20%
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Nickel is a good _________ material?
Magnetic ( not aluminum, tin, copper)
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any voltage of 600 volts or fewer is considered
low potential
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the flow of AC is impeded not only by a circuits resistance bu also by its
Reactance
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visible light occurs at what frequencies?
1,000,000,000 MHz
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direct and continuous current flows always in the same
direction
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the total resistance in a parallel circuit is alway less than the ___________
smallest resistance
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A fuse must be place in _______ with the consuming device
series
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What are the effects of current?
heating, magnetic, chemichal, and physiological
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Which of the following is a term applied to machines that convert either electrical energy into mechanical energy or mechanical energy into electrical energy by utilizing the principles of electromagnetic induction?
Dynamo
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Farads are units of resistance generally associated with
capacitors.
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The relation between currents from different branches arriving at a node in a circuit is given by
Kirchoff's Law
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According to________ Law of current, in a closed network made up of various nodes and branches, the sum of all the currents entering the node is always equal to the sum of all the currents leaving the node.
According to ________ Law, in the above node, I1 + I3 = I2 + I4. So, choice B is correct.
Kirchoff's LAw
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When AC passes through a diode
it rectifies the current
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If two capacitors are connected in parallel in a circuit, the total capacitance of the circuit is equal to the
sum of the capacitance of the capacitors.
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What happens to the resistance and current in a conductor if the length of the conductor is increased without changing the cross-sectional area and the voltage?
- Its resistance increases, but the current decreases.
- (Therefore, when the conductor length is increased, its resistance increases)
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In which configuration of the amplifier will you get the highest power gain?
A common emitter configuration amplifier acts both as a voltage and a current amplifier. In which configuration of the amplifier will you get the highest power gain?
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the propert of a circuit that opposes any change in voltage is
capacitance
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another term for "cycles per second" is
hertz
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the process of trasmitting voice by varying the height of a carrier wave is known as
amplitude modulation
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