Electrical Engineering

electrical banner 3Electrical engineers, abbreviated as EE, design, develop, test, and supervise the manufacturing of electrical equipment.  Electrical & Electronic engineers design things such as power systems, electronics/microelectronics, signal processing, instrumentation & control systems, computers, and computer networks.

 

 

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Nomenclature & Symbols

 

  • \( S_2 \)  -  2-way switch
  • \( S_3 \)  -  3-way switch
  • \( AC \)  -  alternating current
  • \( ASHRAE \)  -  American Society of Heating, Refigeration, and Air-conditioning Engineers
  • \( AWG \)  -  American Wire Gauge
  • \( A \)  -  ampere
  • \( AF \)  -  audio frequency
  • \( BW \)  -  bandwidth
  • \( C \)  -  capacitance or capacity
  • \( X_c \)  -  capacitive reactance
  • \( T_c \)  -  capacitive time constant
  • \( Q \)  -  capacitor quality factor
  • \( CR \)  -  card reader
  • \( CB \)  -  circuit breaker
  • \( G \)  -  conductance
  • \( I \)  -  current
  • \( CT \)  -  current transformer
  • \( DC \)  -  direct current
  • \( DB \)  -  distress button
  • \( F \)  -  fire alarm pull box
  • \( ELEC \)  -  electric
  • \( Q \)  -  electric charge
  • \( G \)  -  electric conductivity
  • \( I \)  -  electric current
  • \( J \)  -  electric current density
  • \( EL \)  -  electric door latch
  • \( ES \)  -  electric door strike
  • \( ELECDR \)  -  electric drive
  • \( E \)  -  electric field
  • \( \phi_e \)  (Greek symbol phi)  -  electric flux
  • \( Q \)  -  electric load
  • \( EMD \)  -  electric motor driven
  • \( EPS \)  -  electric power supply
  • \( \eta \)  (Greek symbol eta)  -  electric performance
  • \( P \)  -  electric power
  • \( R \)  -  electric resistance
  • \( W \)  -  electric work
  • \( ELECT\)  -  electrical
  • \( EE \)  -  Electrical Engineer
  • \( ER \)  -  electrical resistance
  • \( EMF \)  -  electromagnetic field or electromotive force
  • \( ELEK \)  -  electronic
  • \( ELECTC \)  -  electronic control
  • \( EI \)  -  electronic interface
  • \( ES \)  -  electronic switch
  • \( EVM \)  -  electronic voltmeter
  • \( ELMCH \)  -  electromechanical
  • \( E \)  -  energy
  • \( \triangle U \)  -  First Law of Thermodynamics
  • \( f \)  -  frequency
  • \( GFCI \)  -  ground fault circuit interrupt outlet
  • \( Z \)  -  impedance
  • \( L \)  -  inductance
  • \( V_l \)  -  inductive load voltage
  • \( X_l \)  -  inductive reactance
  • \( T_l \)  -  inductive time constant
  • \( J \)  -  junction box
  • \( KE \)  -  kinetic energy
  • \( KB \)  -  knox box - fire department keys
  • \( L_x \)  -  light
  • \( d \)  -  lost capacitor coefficient
  • \( d \)  -  lost coils inductors coefficienta
  • \( LF \)  -  low frequency
  • \( L_m \)  -  luminous flow
  • \( c_d \)  -  luminous efficency
  • \( c_d \)  -  luminous intensity
  • \( NC \)  -  normally closed
  • \( NO \)  -  normally open
  • \( ML \)  -  magnetic door lock
  • \( MAD \)  -  mean annual discharge
  • \( ME \)  -  mechanical energy
  • \( MW \)  -  megawatt
  • \( M \)  -  mutual inductance
  • \( OCV \)  -  open circuit voltage
  • \( PB \)  -  panic button
  • \( POV \)  -  peak operating voltage
  • \( T \)  -  period
  • \( \delta \), \(\; \phi \)  (Greek symbol delta, phi)  -  phase constant
  • \( PE \)  -  potential energy
  • \( P \)  -  power
  • \( \omega \)  (Greek symbol omega)  -  pulsation
  • \( Q \)  -  quality factor of the coils inductors
  • \( SW \)  -  short wave or shortwave
  • \( SD \)  -  smoke detector
  • \( SSR \)  -  solid state relay
  • \( S \)  -  switch
  • \( S_DIM \)  -  switch with built-in dimmer
  • \( RF \)  -  radio frequency
  • \( TCR \), \(\; RTC \)  -  temperature coefficient of resistance
  • \( \rho \)  (Greek symbol rho)  -  resistivity
  • \( L \)  -  self inductance
  • \( T \)  -  temperature
  • \( TX \)  -  transmitter
  • \( \epsilon_0 \)  (Greek symbol epsilon)  -  vacuum permitivity
  • \( VA \)  -  volt/ampere
  • \( VOM \)  -  volt ohm meter
  • \( V \), \(\; E \)  -  voltage/volt
  • \( VCR \)  -  voltage coefficient of resistance
  • \( VD \)  -  voltage drop
  • \( \lambda \)  (Greek symbol lambda)  -  wavelength
  • \( P \)  -  watt
  • \( WP \)  -  weatherproof outlet

 

Electric Wire Materials

  • Copper electrical wire - Copper (Cu) is considered the standard in wiring. Most homes and appliances use copper for two reasons. It is easy to mold or bend and it is a good conductor. Copper is rather easy to come by but not as easy as other conductor metals.
  • Aluminum electrical wire - Aluminum (Al) is also easy to mold and bend but less of a conductor than copper. If you decide to use aluminum wire that will carry the same amount of electricity as a copper wire, the wire needs to have a larger diameter. Since aluminum is more abundant than copper, it makes it the cheaper of the two.
  • Silver electrical wire - Silver (Ag) is the best conductor of electricity for high temperatures. However, it is hard to bend and expensive.
  • Alloys in electrical wire - In manufacturing, an alloy may sometimes be used. Aluminum and copper can be used for cost and conductibility.

  

Electrical Engineering Glossary

A

  • Active component  - Components in a circuit that need external power.
  • Actuator  -  A device used to open, close, or control valves.
  • Alternator  -  A device which converts mechanical energy into electrical energy used to maintain a charge in a car battery.
  • American Wire Gauge  -  A measure of wire thickness.
  • Ammeter  -  An instrument for measuring the flow of electrical current in amperes.
  • Amp  -  Amp is a unit of current.
  • Amphere  -  A unit of measure for the flow of current in a circuit.
  • Amplifier  -  A device that amplifies a relatively small input signal.
  • Analog  -  Analog or analogue is a continuous electronic variable signal caring information.
  • Analog switch  -  A switching device able to rought analog signals.
  • Arcing time of fuse  -  After the breaking of a fuse wire there will be arcing between both melted tips of the wire which will be extinguished at the current zero.

B

  • Basic circuit  -  Has a power source, wires connecting components, and components.
  • Base load  -  That part of the electricity demand which is continuous and does not vary over a 24-hour period.
  • Base power  -  Power generated by a utility unit that operates at a very high capacity.
  • Battery  -  A storage device for energy and then discharge.  Batteries can be rated by their energy capacity.
  • Branch circuit  -  A portion of the wiring system extending beyond the final overcurrent protective device.
  • Breaker  -  An automatic switching device that disconnect the power to a circut when the current or heat exceeds a certain level for a certain amount of time.
  • Broadband  -  A transmission medium with enough bandwith to cary multiple channels, data, video and voice at the same time.
  • Buffer  -  An autio signal device.

C

  • Capacitor  -  Behaves as a charge storage device.  Holds an electric charge when voltage is applied across it and gives up the stored charge when required.
  • Capacitance  -  The ability to hold an electric charge.
  • Cartridge fuse  -  The fuse wire is enclosed in a transparent glass bulge or tube completely sealed.
  • Cell  -  Cells generate energy through a thermal process, chemical or optical.
  • Charge  -  Causes objects to feel an attraction or repulsive force toward one another.
  • Circuit  -  A closed loop through which electricity can flow.  The flow of current is from positive to negative.
  • Conductivity  -  The amount of current that a material can conduct.
  • Conductor  -  A material through which heat passes and allows the free flow of electric charge.
  • Contacts  -  Components
  • Coulomb's law  -  The magnitude of the electrostatic force between two electric charges.
  • Current  -  The rate of flow of electricity in a circuit, measured in amperes.
  • Current density  -  The amount of electric current flow through a unit value of the area cross-section.
  • Current rating of fuse  -  The maximum value of current due to which fuse does not melt.
  • Current transformer  -  Used to supply information for measuring power flows and the electrical inputs for the operation of protective relays associated with the transmission and distribution circuits or for power transformers.

D

  • Daniell cell  -  A copper vessel containing copper sulfate solution.
  • Diode  -  A device allowing the current to flow as a one-way switch only and restricting the current from flowing in the opposite direction.  Diodes allow the current to flow when the anode is positive and the cathode is negative.
  • Diode bridge  -  A combination of four diodes that are connected togeather
  • Diode types  -  avalanche diode, laser diode, light emitting diode, photodiode, PIN diode, PN junction diode, schottky diode, tunnel diode, varactor diode, and zener diode.
  • Direct current  -  An electric current that flows in only one direction.
  • Distribution bus  -  A steel structure of switches used to route power out of a substation.
  • Distribution transformer  -  Reduces the voltage of the primary circuit to the voltage required by customers.
  • Discharge  -  The conversion of chemical energy of a battery into electric energy.
  • Double pole  -  A switch device that opens, closes, or changes connection of two conductors in an electrical circuit.
  • Double throw  -  A switch that opens, closes, or completes a circuit in both extreme positions of its actuator.
  • Dry circuit  -  A low current circuit that does not generate enough power to generate an arc.
  • Dump circuit  -  A way to remotely trip a circuit breaker without there having to be a current overload.
  • Dust proof  -  Constructed or protected so that dust will not interfere with its operation.

E

  • Electric charge  -  A basic characteristic of matter that is based on the balance of protons (positive charge) and electrons (negative charge).
  • Electric circuit  -  They combine components, wires, and electricity to accomplish some functions.
  • Electric grid  -  An intergrated system of electricity distribution normally over a large area.
  • Electric potential  -  Difference in the electric charge between two points in a circuit, it's called voltage.
  • Electrolyte  -  A compound that produces ions when dissolved in water and having either a positive of negative charge.
  • Electron  -  A subatomic particle found in all atoms, electrons carry electricity by flowing from one atom to the next in a conductive material.
  • Electromagnetic relay  -  A switch that is controlled by an electrical circuit using the relay coil to physically move a mechanical switch.
  • Electromagnetism  -  A branch of physics that deals with the motion of electric currents and magnetic fields.
  • Energy  -  It is never created or destroyed First Law of Thermodynamics, but it can be transferred from one object to another.
  • Explosion proof  -  Designed and constructed to withstand and internal explosion without creating an external explosion or fire.

F

  • Field  -  An invisible space around a charged particle where an electric force is exerted on other charged particles.
  • First Law of Thermodynamics  -  This means that the total amount of energy in the universe is constant and that it can neither be created or destroyed.  This law states that for every gain in some type of energy will result in the loss in some other form.
  • Flammable liquid  -  Any liquid having a flash point below 100 deg F and having a vapor pressure not to excede an absolute pressure of 40 psi.
  • Float switch  -  An electrical switch operated by a fliud flow.
  • Flux  -  How much of something goes through a given area.
  • Forward biased diode  -  The external voltage which is applied across the PN-diode for reducing the potential barrier to constitute the easy flow of current.
  • Frequency  -  The number of cycles per sec, measured in Hertz.
  • Fuse  -  An safety device that removes electrical current from a circuit when the current is two high.
  • Fuse law  -  The current carring capacity of a fuse wire.
  • Fuse wire  -  Can carry the normal current without excessive load, but with to much load it rapidly heats up and melts.
  • Fuse wire materials  -  Mainly aluminum, antimony, copper, lead, silver, tin, and zinc.
  • Fusing factor  -  The ratio of minimum fusing current and current rating of the fuse.

G

  • Galvanic separation  -  Instead of using a physical connection to activate the relay, the connection will have to be made using LED or infrared light.
  • Generator  -  A mechanical device that produces electrical energy from mechanical energy.
  • Gigawatt  -  One billion watts.  One million kilowatts.  One thousand megawatts.
  • Grid  -  A system of power lines and generators.
  • Grounded conductor  -  A system or circuit conductor that is intentionally grounded, using gray or white in color.
  • Grounding  -  The removing of excess change on an object by transfering electrical charges from a short circuit between this object and another larger object.
  • Grounding conductor  -  Used to connect metal equipment enclosures amd/or the system grounding conductor to a grounding electrode.
  • Grounding transformer  -  Intended primarily to provide a neutral point for grounding.
  • Ground fault  -  When an underground conductor comes in contact with anything that is grounded.
  • Ground fault circuit interrupter  -  A device for the protection of personal that functions to de-energize a curcuit.

H

  • Hertz  -  A measure of frequency or cycles per second (cps).
  • Horsepower  -  A measure of power or the rate of doing work.

I

  • Ignition coil  -  A device used to supply DC voltage to the spark plugs.
  • Impedance  -  The total effects of a circuit that opposes the flow of an ac current consisting of capacitance, inductance, and resistance.
  • Inductance  -  The measure of an electric conductor or circuit by which an electromotive force is induced in it.

  • Induction motor  -  The power is transfered to the rotor winding by the stator through induction.  The induction motor always runs at a speed lower than synchronous speed.
  • Inductor  -  An energy storage device which stores energy in the form of a magnetic field.
  • Insulator  -  Opposes the flow of electricity and keep us safe.
  • Invertor  -  An electrical which is designed to convert direct current into alternating current.

J

  • Joule’s law  -  The amount of heat (energy) delivered to something.
  • Jumper  -  A short length of a conductor used to make a connection between terminals.

K

  • Kinetic energy  -  The energy in moving objects or mass.  If it moves, it has kinetic energy.

L

  • Led  -  Emits energy in the form of light instead of energy.
  • Load  -  A device that consumes electrical power and is connected to a source of electricity.
  • Low voltage  -  Defined as 50 volts or less.

M

  • Magnetic field  -  Magnetic fields never cross, never start or stop, where the field is strongest lines bunch togeather and can be seen clearly seen in the real world.
  • Magnetic flux (\(\phi\) or \(\phi_B\))  -  The number of magnetic field lines passing through a given closed surface.
  • Magnetic switch  -  Depending on the switch configuration for on and off, the switch is activated when the magnetic field is detected.
  • Mechanical energy  -  The sum of the change in kinetic energy and potential energy generating from the force of gravity, external forces or the movement released in machine movement.
  • Mechanical relay  -  Has moving parts.
  • Melting time of fuse  -  The time taken by a fuse wire to get broken by melting.
  • Minimum fuse current  -  The minimum value of current due to which fuse ments.  Can carry the normal current without excessive load, but with to much load it rapidly heats up and melts.
  • Motor  -  Converts the electric energy to mechanical energy.
  • Motor efficiency  -  The ratio of shaft power power out and electric power input of a motor.
  • Mutual inductance  -  The inductance of a coil due to current in another nearby coil.

N

  • Normally closed  -  The circuit is closed when the switch is not open.
  • Normally open  -  The circuit is open when the switch is not operated.

O

  • Off-peak rate  -  The rate of cost for power used during off-peak periods.
  • Ohm  -  A unit of resistance.
  • Ohm's law  -  The relationships between power, voltage, current, and resistance.
  • Operating time of fuse  -  The time gap between the instant when the overall current starts to flow through the fuse and the instant when the arc in the fuse finally gets extinguished.
  • Operational amplifier  -  A voltage amplifier with very high gain.
  • Overload protection  -  Protect the motor by monitoring the current flow in the circuit.
  • Overload protection relay  -  These relays have a trip class rating for different applications.  This is usually sufficient time for the motor to reach full speed.
  • Overload relay tripping  -  The time taken by the relay to open in an overload condition.

P

  • Parrallel circuit  -  The parts are arranged in branches each going their own way.
  • Parrallel resistor  -  Resistors are arranged in branches each going their own way.
  • Passive component  -  Components that do not require any external power.
  • Phase constant  -  How much displacement a wave is from an equilibrium or zero position.
  • Potential energy  -  The possessed energy by a body due to its relative position in a gravitational field
  • Power  -  The rate of doing work and is measured by the amount of foot pounds of work done in a particular unit of time.
  • Power density  -  The ratio of the power available from a battery to its mass or volume.
  • Power factor  -  The ratio of the average power and the apparent volt-amperes.
  • Preset resistor  -  The resistance is adjusted with rotary control pressure on top with a screw driver.
  • Primary cell  -  A dry cell and not a rechargeable cell.  A chemical reaction between electrodes and electrolites causing a permanent change.
  • Prospective current in fuse  -  The value of current which would flow through the fuse immediately after a short circiut occures in the network.

Q

  • Quick disconnect  -  A type of connector that permits rapid locking and unlocking of two connector halves.

R

  • Rated flow  -  The maximum flow that the power supply system is capable of maintaining at a specific operating pressure.
  • Rated voltage  -  The maximum voltage at which an electric component can operate for extended periods without undue degradation of safety hazard.
  • Rectifier  -  An electrical device that convert alternating current (AC) to direct current (DC).
  • Relay  -  A type of electric switch that is operated by an electromagnet which charges over the switching when current is applied to the coil.  Types of relays are electromagnetic relay, solid state relay, thermal relay, and time relay.
  • Resistance  -  The ability to resist or prevent the flow of current.
  • Resistor  -  Resists the flow of electricity.
  • Reverse biased diode  -  The external voltage which is applied to the PN junction for strengthening the potential barrier and prevents the flow of current.
  • Right-hand rule  -  When current is flowing through a wire, the magnetic field rotates around the wire.  The direction of the current determines the direction of the magnetic field.
  • Rotor  -  The rotating element of an induction motor.

S

  • Secondary cell  -  A wet cell and is a rechargable cell.  Generates a current through a secondary cell in the opposite direction of the first cell.
  • Self inductance  -  The inductance of a coil or inductor due to its own current.
  • Semiconductor  -  A type of material that has an electronic resistance between the metal and the resistance insulator.
  • Series circuit  -  The parts are connected end to end.
  • Series resistors  -  Resistors connected end to end.
  • Service conductor  -  Supply conductors that extend from the street main or transformer to the service equipment of the premises being supplied.
  • Service  -  The equipment and conductors that transmit electricity from the utility supply system to the building being served.
  • Service drop  -  Run of cables from the power companies aboveground lines to the point of connection to the customer's premises.
  • Service equipment  -  The necessary equipment, usually a circuit breaker or switch and fuses and their accessories.
  • Service point  -  The point of connection between the facilities of the service utility and the premises wiring.
  • Shockley diode  -  Has fast switching operation.
  • Short circuit  -  A low resistance connection unintentionally made between points of an electrical circuit which may resullt in current flow far above normal levels.
  • Shunt  -  Also called a shunt resistor, is a conductor joining two points in a circuit used to limit the speed of the current.
  • Single-phase  -  An ac electric system or load consisting of at least one pair of conductors energized by a single alternating voltage.
  • Solar constant  -  The strength of the sun.
  • Solar energy  -  Energy from the sun.
  • Solenoid  -  A device made of a coil of wire.  When current is introduced a magnetic field is formed around the coil (electrical energy) and the plunger is pulled in (mechanical work).  When the current is removed the plunger is released.
  • Solid state relay  -  Has no moving parts and relys on either infra-red light emitting diodes or LED couplers to operate.
  • Spent fuel  -  Fuel assemblies removed from a reactor after use.
  • Static electricity  -  The build up of an electric charge on the surface of an object.
  • Stator  -  The stationary element of an induction motor.
  • Surge capacity  -  The ability of an electrical supply to tolerate a momentary current surge or inrush imposed by the starting of motors or the energizing of transformers.
  • Switch  -  A device that opens and closes electrical circuit.
  • Synchronous speed  -  The speed of the magnetic field in the stator.

T

  • Thermal insulator  -  Does not conduct heat readily and is used for either heat conservation or personnel protection.
  • Thermal overload relay  -  This device works on the heat produced by the excessive overload current.
  • Three-phase  -  An ac electric system or load consisting of three conductors energized by alternating voltage that are out of phase by one third of a cycle.
  • Time delay relay  -  A relay that when the input action signal is added, the output circuit needs to pass through the specified accurate time to produce jump charge.
  • Transformer  -  A device that uses electromagnetism to convert one current to another current.
  • Transformer vault  -  An underground structure in which power transformers, circuit breakers, voltage regulators, and etc. are housed.
  • Transducer  -  A voltage output device used for convert energy to another form.
  • Transmitter  -  A current output device used for communication electronic signals over a distance.
  • Transmission bus  -  Steel structure arrays of switches used to route power in a substation.
  • Transmission line  -  Transmits high-voltage electricity from the generation source or substation to another substation in the electric distribution system.
  • Triac  -  An electrical componeht approximately equal to two silicon-controlled rectifiers joined in inverse parallel and their gates connect togeather.
  • Trickle charge  -  Charging at a low rate.
  • Tripping class  -  Defines the starting time at a specific current before tripping occures.  The number in the trip class is the total number of seconds that the motor is allowed to overload before the circuit trips.
  • Tuner  -  A circuit that can pick signals from a frequency from a group of signals of different frequencies.

U

V

  • Varactor diode  -  The capacitance varies according to the applied input voltage.
  • Variable capacitor  -  Used in tuning the circuit to a required frequency.
  • Variable indicator  -  Allows the value of the inductance to be changed.
  • Volt  -  A unit of electrical pressure.
  • Voltage  -  The amount of pressure that will cause one ampere of current in one ohm of resistance.
  • Voltage drop  -  When the voltage at the end of the cable is less than the beginning of the cable.
  • Voltage rating  -  The maximum voltage at which a cable or insulated conductor can be safetly maintained during continuous use in a normal manner.

W

  • Winding  -  All of the coils of a generator.

X

Y

Z

 

 

Display #
Title
Alternating Current
Alternating Current to Direct Current
API RP 500, Appendix B - Minimum Air Induction Ratio to Achive Adequate Ventilation Using Fugitive Emissions
API RP 500, Section 10
API RP 500, Section 11
API RP 500, Section 12
API RP 500, Section 14
API RP 500, Section 6
API RP 500, Section 8
API RP 500, Section 9
API RP 500, Ventilation
Area Classification Drawing
Control Narrative
Current
Direct Current
Electric Field
Electric Flux
Electric Power
Electric Resistance
Electrical Conductivity
Ohm's Law
Resistor
Resistors in Parallel
Resistors in Series
Solenoid

Tags: Equations for Electrical