PRINCIPLES OF ELECTRICITY Flashcards
Natural phenomenon that occurs throughout nature and takes many different forms. Presence and flow of an electric charge.
Electricity
Electricity is a _____________ that occurs throughout nature and takes many different forms. Presence and flow of an ______________.
Natural phenomenon |Electric charge
is a mysterious incomprehensible entity which is invisible and visible at the same time
Electricity
Electricity is a mysterious incomprehensible entity which is __________and __________ at the same time
invisible| visible
is a fundamental part of our modern world, powering
everything from our lights and appliances to our computers and transportation systems
Electricity
Also referred to as an energy carrier, which means it can be converted to other forms of energy such as
mechanical energy or heat
Electricity as Energy
Electricity as energy also referred to as an energy carrier, which means it can be converted to other forms of energy such as ________ or ____________
mechanical energy or heat
The bulk of electric energy utilized today is in the form of
alternating current (a-c), produced by a-c generators, commonly called alternators. Direct-current (d-c) generators
are utilized for special applications requiring large quantities of d-c.
Electric Energy
A generator that converts mechanical
energy into electrical energy in the form of alternating current is called?
Alternating Current Generator or AC Generator
A type of generator that are highly efficient for long
distance power transmission due to the ability to step-up or step-down voltages using
transformers
Alternating Current Generator or AC Generator
Alternating current (AC) Generator also known as?
Alternators
Direct current (DC) Generator also known as?
Commutator
A machine that converts mechanical energy
into DC (direct current) electricity is a?
DC Generator or Direct Current Generator
Provides a constant voltage and current, making it suitable for applications requiring a steady power supply. However, _________ generators are less efficient for high-power applications and long-distance transmission
DC Generator or Direct Current Generator
Unit or electric current
Amperes or amps
measures how many of these electrons are flowing past a specific point in the wire every second.
Current
Numerically, an ampere of current flows in a conductor when __________ electrons pass a given cross section in _______ second
6.25 x 1018 electrons | 1 second
Unit of electric potential
Volt or ohm
The electron movement and its concomitant energy, which constitutes electricity, are caused by creating a higher positive electric charge at one point on a conductor than exists at another point on that same conductor.
Volt
By ______ current is assisted to flow from positive (+) to negative (-)
Convention Current
This difference in charge can be created in
several ways. the _______ the voltage (pressure), the ________the current (wow) for
a given resistance (friction
the higher the voltage the higher the current
The flow of fluid in a hydraulic system is impeded by friction; the flow of current in an electric circuit is impeded by resistance, which is the electrical term for friction
OHM
The flow of fluid in a hydraulic system is impeded by ________
Friction
In a direct-current circuit (d-c), this unit is called _________ and is abbreviated ________
Resistance | R
in an alternating-current circuit (a-c), it is
called ___________ and is abbreviated _________.
Impedance | Z
In a direct-current circuit (d-c), this unit is called resistance and is abbreviated R; in
an alternating-current circuit (a-c), it is called impedance and is abbreviated Z. The
unit of measurement is called the _______
OHM
__________states that the current I that will flow in a d-e circuit is directly proportional to the voltage V and inversely proportional to the resistance R of the circuit
Ohm’s Law
According to Ohm’s Law it is analogous to water pressure
Voltage
Formula of Ohms Law
Current = Voltage/Resistance
or
i = V/R
According to Ohm’s Law it is the amount of water flowing through the pipe
Current
According to Ohm’s Law it is is the size of the pipe.
Resistance
According to Ohm’s Law more water will flow through the pipe (current) when ________is applied (voltage) and the________ (lower the resistance)
more pressure | bigger the pipe
2 types of circuit arrangements
Series Circuit
Parallel Circuit
An electric circuit may be defined as a complete conducting path that carries current from a source of electricity to and through some electrical device (or load} and back to the source. A current can never flow unless there is a complete (closed) circuit.
Series Circuit
A circuit wherein the elements are connected one after the other in series. Thus, the resistance and voltages add
Series Circuit
In any series circuit, the _____________ is the sum of the resistance around the circuit
Total Resistance R
The battery voltage may be called?
Vab = 120v
The voltage across the load resistance
Vcd = 115v
The resistance of the two wires
rbc = rda = 0.04 ohm
When two or more branches or loads in a circuit are connected between the same two points, they are said to be connected in _______ or multiple
Parallel Circuit
Loads connected in parallel are equivalent to _________
superimposed into a ___________.
separate circuits |single connection
is the standard
arrangement in all building wiring. A typical lighting and receptacle
arrangement for a large room.
Parallel Connection
Two types of current
Direct Current | Alternating Current
Type of current wherein the flow of electric current takes place at a constant time rate, practically unvarying and in the same direction around a circuit.
Direct Current
Whenever the flow of current is
periodically varying in time and in direction, as indicated by the symmetrical positive and negative loops or sine waves, it is called an _________.
Alternating Current
Types of Alternating Current
Alternating Current
fully rectified
Half-rectified
Fully-rectified and filtered
Enumerate the following electric power generation
Direct Current (d-c) Generation
Alternating (a-c) Generation
It is actually an AC generator with a commutator that converts AC to DC.
DC Generator
The main source of
DC Power
Batteries
Mostly used where accurate speed control is desired or where d-c is required on a larger and more sustainable basis than would be economical for a battery.
DC Generator
Components of d-c generator
Prime Mover
Commutator
Rectifiers
A component of d-c generator that provides mechanical energy (e.g. motor, engine, turbine)
Prime Mover
A component of d-c generator that converts AC to DC
Commutator
A component of d-c generator that can also convert AC to DC (materials used include selenium, silicon, copper oxide)
Rectifiers
As the conductor moves through the magnetic field, it cuts the magnetic field lines. This movement causes a change in the magnetic field experienced by the conductor. This change in the magnetic field induces an electric potential (voltage) across the ends of the conductor. If the conductor is part of a closed circuit, this voltage will cause an electric current to flow.
Faraday’s Law of Electromagnetic Induction
This _______________________ states that when an electrical conductor is moved in a magnetic field, a voltage is induced in it. The direction of the movement determines the polarity of the induced as shown.
Principle of Electromagnetic Induction
Converts mechanical energy into a-c electricity and uses magnetic
induction to generate electricity
Alternating Current (a-c) Generator
Alternating current is produced
commercially by an a-c generator, called
Alternator
is picked off with sliding contacts, called “slip-rings”. It does not matter whether the conductor moves and the magnetic field is stationary, or vice versa, as long as there is relative motion between the two.
Voltage
Voltage is picked off with sliding
contacts, called ________
slip-rings
is the technical term for the more common expression -work.
Energy
is synonymous with fuel and therefore also cost.
Energy
is a broad term that refers to the ability or capacity to do work.
Energy
According to the law of conservation of energy, energy can be converted from one form to another, but the total amount of energy in a closed system remains__________
constant
is an energy associated with the flow of electric charge.
Electric energy
It is a form of potential and kinetic energy combined.
Electrical Energy
powers various electrical devices, appliances, and systems. It’s a subset of the broader concept of energy, focusing specifically on the energy derived from electrical phenomena.
Electric Energy
Type of materials that allows the flow of electric current
Conductors
Type of materials that resists the flow of electric current
Insulators
Formula of energy or work
E = PT
or
Energy = Power x Time
The rate at which work is done
Power
It is a measure of how long the energy can be converted from one form to another or how long it can be transferred from one system to another.
Power
is the rate where an electrical energy is consumed or transferred in a circuit
Electric Power
Formula of power
P=W/t
or
Power = Watts/time
Unit of power
Horsepower
Hour
Watts (W)
Kilowatts (kW)
Joule per second (J/s)
Calorie per second (C/s
Different formula of power
P = IV
P = I^2 (R)
P = (V^2)/R
V = IR
W = I(IR)
W = I(V)
