Electricity PowerPoint and Blackboard Content
The average dry human body has ____________ Ω resistance, while a soaking wet body may have as little as ___________ Ω resistance.
100,000, 1,000
The higher the _________, the more protective the fabric from arc flash.
ATPV
Power =
Amperage x Voltage
The flow of electrical charge is measured in _________
Amperes (A)
What does ATPV stand for?
Arc thermal protective value
____________ ___________ assumes that current flows out of the positive side of the battery, through the circuit, and back to the negative side of the battery. This convention was established when electricity was first discovered, but it is incorrect!
Conventional Current
_____________ consists of connecting an object to the earth with metal, usually copper wire
Grounding
___________ _____: is a measure of the total opposition to flow of current in an AC circuit due to both resistance and reactance.
Impedance (Z)
The sum of all the voltage drops (VR1 + VR2 + VR3) equals the total applied voltage (VT). This is called _______ _______ Law.
Kirchhoff's Voltage
Z = √(R^2 + [(X sub ____) - (X sub _____)]^2)
L, C
Formula for calculating power in a single-phase AC circuit: Power (_______) = _____ x ____cos θ
RMS, voltage, current
___________ is a property that represents opposition to current flow in AC systems due to reactive components like ___________ and _____________.
Reactance, capacitors, inductors
___________ is The opposition of current flow, measured in __________
Resistance, ohms
V peak = __________ x √2
V RMS
V RMS = ________ / √2
V peak
Resistance =
Voltage / Current
Current =
Voltage / Resistance
_____________ is The force (pressure) that causes current to flow, measured in _______
Voltage, volts (V)
Power is measured in:
Watts
One __________ is equal to one _________ of charge moving past a point in one second.
ampere, coulomb
The ___________ is the maximum value reached by the waveform during each cycle. It represents the highest positive or negative value from the reference level
amplitude
In electrical formulas and equations, you will see voltage symbolized with a capital E or V for steady or __________ values, or with an e or v for ________-_________ values.
average, time-varying
____________ means connecting two objects together with metal, usually a piece of copper wire
bonding
in parallel circuits, _______ ______ of components are connected together, and there are ______ _______ for current to flow
both ends, multiple paths
(X sub C): Capacitive reactance occurs in circuits containing ____________. When AC voltage is applied to them, it causes a ___________ _____ ________ between the plates, resulting in the accumulation and discharge of energy.
capacitors, displacement of charge
the negative/negative terminals in a DC circuit are also referred to as ________.
commons
With direct current, the voltage is a _________ value.
constant
The __________ (unit symbol: C) is the unit of quantity of electric charge
coulomb
Resistance decreases __________.
current
Voltage =
current x resistance
When measuring __________, Set multimeter to the proper ADC range. __________ flow must go through the meter.
current, circuit
Electrical power is directly related to the amount of ________ and _________ within a system.
current, voltage
The meter may be __________ if voltage is present when testing for continuity or resistance. Always ___________ circuits when measuring continuity or resistance.
damaged, de-energize
DC voltage represents the _________ _____ _________ from the positive side of the battery or source to the negative side of the battery or source.
difference in charge
Current in a resistor varies in __________ __________ to the voltage applied to it and is __________ _________ to the resistor's value
direct proportion, inverse proportion
Inductive reactance is _______ _________ to the frequency of the AC signal so is less significant at ________ frequencies.
directly proportional, low
lights, motors, heating elements, electronic devices, etc., are all examples of what?
electrical loads
_________ _________ is the rate at which electrical energy is transferred or converted from one form to another in an electrical circuit.
electrical power
science disciplines use__________ _________, whereas the engineering disciplines use __________ __________, when discussing the flow of electrons
electron flow, conventional current
Electricity is the movement of _______
electrons
The __________ flow out of the negative side of the battery, through the circuit, and back to the positive side of the battery. This is known as ___________ _______ and is the correct way electricity flows from a battery.
electrons, electron flow
In series circuits, components are connected ________ _____ _______, and there is only _____ ______ ______ for current to flow
end-to-end, a single path
an _________ ________ _______ is any physical device that prevents the transmission or release of hazardous energy. This may include (but is not limited to) circuit breakers, disconnect switches, valves, blocks, toggles, etc.
energy isolating device
The current flowing through every component in a series circuit is __________.
equal
•The voltage across every parallel component is _________.
equal
the RMS value of an AC current is the __________ _________ value of DC current that would produce the same power dissipation in a resistor as the AC current through the same resistor.
equivalent steady
•Because extra electrons will always flow from the negative side to the positive side, direct current will always flow in the same direction in a circuit. Another way to say this is that DC has __________ _________.
fixed polarity
The ___________ of a periodic waveform is the number of complete cycles or oscillations that occur in one second. It is measured in ___________.
frequency, Hertz (Hz)
Electrical equipment is ___________ first for the protection of personnel and second for the protection of equipment.
grounded
A phase shift of 0 degrees means the waveforms are ______ _______, while a phase shift of 180 degrees means they are _____________ ______ _____ __________.
in sync, completely out of phase
(X sub L): Inductive reactance arises in circuits containing ___________. When AC voltage is applied to them, it induces a magnetic field that ________ ________. Changes in the magnetic field cause an opposing voltage that leads to a phase shift between voltage and current.
inductors, stores energy
Chemical reactions, electromagnetic induction, the photovoltaic effect, and the Seebeck effect, are all ways that current can be ________ and _________
initiated, sustained
Capacitive reactance is _____________ ______________ to the frequency of the AC signal so is less significant at ______ frequencies.
inversely proportional, high
Lock-out tag-out is Designed to ________ or ______ _______machines & equipment from their power sources before any work is carried out.
isolate, shut off
Electricity is a force that can provide _______, ________, _________, and __________ when converted
light, heat, sound, motion
3 phase electricity __________ the time between peak voltage, creating more __________ power.
minimizing, consistent
A parallel circuit contains _______ ______ ______ path for current flow
more than one
A digital multimeter will give a __________ reading if the positive and negative terminals are reversed.
negative
_________ milliamp(s) is the "threshold of perception"
one
1 megohm = ______ _________ ohms.
one million
Resistance is a property of a material or component in an electrical circuit that _________ the flow of electric current. When a voltage is applied across a circuit component, its resistance __________ the flow of charged particles and reduces the __________ of the current.
opposes, restricts, magnitude
The _____________________ value is the difference between the maximum positive and maximum negative values in a waveform. It represents the _______ _______ of voltage variation.
peak-to-peak, total range
The ____________ of a periodic wave is the time it takes for one complete cycle to occur. It is the reciprocal of frequency and is measured in ___________.
period, seconds
A __________ __________ is a quantity (voltage, current, power, for example) that varies in a repeating pattern over time.
periodic waveform
A ________ ______ ______ is Part of an organization's Safety Management System (SMS), Utilized as an ______________ __________, and is used to ensure that work is carried out in the ________ ________ manner.
permit to work, administrative control, safest possible
________ _________ refers to the time difference between two periodic waveforms
phase shift
Photovoltaic effect: When sunlight strikes the surface of a solar cell, __________ are absorbed by the semiconductor material used in the cell which causes some ___________ to break free from their normal positions, creating a charge imbalance.
photons, electrons
Lockout is a device that ___________ prevents the energization of equipment or machinery by _____________ operation of the energy isolating device. It cannot be operated until the lock has been removed.
physically, preventing
The positive and negative signs represent _________ and _______.
polarity, flow
The chemical reaction inside the battery causes electrons to move from the positive terminal to the negative terminal, making the negative terminal more negative and the positive terminal more positive. This creates a ________ __________ , or voltage across the battery terminals.
potential difference
Whenever a _________ __________ exists between two points in a circuit, whether created by a battery, a generator, or some other voltage source, it will drive electrons from the more negative point toward the more positive point. This is called _________ _______, or _________ _________.
potential difference, electron flow, electron current
All __________ ________ should be regularly inspected for abrasion or cracking of insulation, and repaired immediately
power cords
cos θ is referred to as the ________ ______
power factor
Any ________ ________ showing evidence of electrical problems should be taken out of service immediately
power tool
Electromagnetic induction, whereby mechanical power supplied by a ________ ________ is converted to electrical power by means of a changing magnetic field; used by electrical ___________.
prime mover, generators
battery provides voltage that will ______ _______ through the bulb when the switch is on.
push current
•The total resistance (R sub T) is equal to the _________ of the ______ of the __________ in a parallel circuit
reciprocal, sum, reciprocal
When measuring ___________, Set the multimeter to the proper _______ range. Measure across the tested component, and the _________ must be off or removed from the circuit.
resistance, ohms, power
__________ are components that create resistance.
resistors
the polarity of AC voltage ___________ with every revolution.
reverses
The ________ _______ ______ ______ is a mathematical concept used to represent the effective or average value of a varying quantity, such as voltage or current, in an AC waveform. It provides a way to express the ___________ of an AC signal in a manner that is equivalent to the magnitude of a DC value.
root mean square (RMS), magnitude
While DC is found in nature, AC is manmade. AC is produced by the __________ of the ___________ relative to an electromagnetic field.
rotation, conductor
Because of electrical inertia (inductance), an arc occurs when two contacts are ____________
separated
If the path of current flow is open at any point in a _______ _______, the current stops flowing to all components
series circuit
reactive elements cause the current and voltage waves to ______ ______ of phase. An inductor will cause the current to _______ behind the voltage, while a capacitor will cause the current to _______ the voltage.
shift out, lag, lead
Arc flashes occur when an arc ___________ across components in a system and creates an ultraviolet flash that can permanently blind a person, plus temperatures of ___________ degrees F can occur, vaporizing metal into a gas, and heating the air so that it creates a pressure wave called an ________ _______
shorts, 35000, arc blast
The reversal of polarity, when graphed, follows a mathematical ________ _______ pattern. The voltage is _______ when the conductor and field are parallel, not perpendicular.
sine wave, zero
A three-phase system is made up of 3 interconnected ____________ __________circuits, and are ______ degrees rotated relative to each other.
single-phase, 120
When electricity jumps a gap in air, it is called a _________
spark
static electricity is a __________ ________ which can ignite a flammable mixture
spark discharge
reactance is associated with the ___________ and __________ of energy in the electric or magnetic fields of the reactive components.
storage, release
The ________ of all of the currents in each branch is equal to the total current (IT). This is called Kirchhoff's Current Law.
sum
the total resistance in a series circuit is equal to the _______ _____ _____ _________ within the circuit
sum of all resistances
Tagout is a ________ or prominent ________ ________ placed on the energy isolating device to indicate the equipment or machinery may not be used until the tag has been removed.
tag, warning device
The Seebeck effect is a phenomenon where a small current is produced between two different types of metals or semiconductor materials when a ___________ ___________ exists between them. Thermocouples use this principle to produce electric signals for __________________ measurement.
temperature difference, temperature
A voltage source (power supply) such as a battery or generator is connected to the attached circuit at two points called the __________.
terminals
The amplitude (height) of the sine wave is the __________ of the circuit
voltage
You cannot have amperage draw without _________
voltage
__________ in an electrical system is equivalent to pressure in a fluid system
voltage
When measuring __________, Set the multimeter to the proper V range. Measure ________ a component.
voltage, across
