EMF
Electromotive force  the voltage developed by any source of electric energy
Conductor, Insulotor, semiconductor
conductor materials that exhibit low resistance to current flow like silver, copper, gold, aluminum Insulator materials that exhibit high resistance like glass, mica, dry woods and plastics Semiconductor neither good nor bad conductor (silicon and germanium. By contaminating/doping a semi conductor you can increase its conductivity.
Electromagnetism
fundamental force of nature which consists of electricity and magnetism the interactive relationship between electric charge and magnetic flux
Electric charge
the force protons and electrons exert
Principles of electromagnetism
moving electrically charged particles create magnetic fields magnetic fields attract or repel moving charged particles moving magnetic fields near charged particles causes current flow
Resistance
the difficulty to pass an electric current through a conductor
Current Flow
When electric charges move through a conductor
Voltage
basically electrical pressure (similar to hydraulic pressure) for electric current to flow there must be a difference between two points of the supplying device a one volt potential difference causes one ampere of current to flow through a resistance of one ohm. Symbol used in math is “E”. the potential difference between the positive and negative terminals of a battery causes current flow
Amperes
rate of flow of electrons (current flow) in an electrical circuit one amp flows when an EMF of one volt is applied across a resistance of one ohm. Symbol in math is “I”. Induced or force compatible to rate of flow in hydraulics measured in current flow
Frequency
the number of cycles an alternating current generates per second standard power line frequency is 60 cycles per second or 60 hertz
Hertz
unit of frequency which is one cycle per second number of times the current is refreshed (turned on/off) per second
Electric Current
direct current  the flow of free electrons in the conductors of the circuit all flowing the same direction
Direct current has fixed polarity
alternating current is when the flow changes direction continuously and regularity.
Direct Current Uses
charging rechargeable batteries operating electronic equipment operating dc motors welders industrial electromagnets
Polarity
direction of current flow when the direction stays in the same direction it is fixed polarity as it is with direct current  it can be positive or negative when it changes constantly as it does with alternating current it is called instantaneous polarity
Direct Current Sources
portable welders car battery solar energy cells
Electrical Circuits
the path an electric current follows  there can be open circuits when the path is incomplete because the switch is open there is a closed circuit which is a complete circuit where there is nothing preventing the current from flowing through the entire circuit
Phases of power sources
single phase and three phase are most common phase indicates the relationship in time (in degree of rotation) between current and voltage power sources deal with either a single time frame for voltage or more than one time for more than one voltage
Single phase
a single voltage (rising and falling potential) that creates a potential difference between two conductors
Series Circuits
 when they are connected end to end or in tandem
 total voltage in a series circuit must add up to each component connected in the series and all voltage is used up before it gets to the end of the line
 remember to think math when reading each question even if its not an equation cause the triangle help answers about voltages, etc…
Three Phase
three different voltages that interact to produce potential differences between the three conductors that supply the three phase loads
Watts
 one amp per second flowing under the potential difference of one volt.
 746 watts = 1hp
 watts = amps x volts
Watt’s Law Triangle
 “P” power in watts
 “I” current in amps
 “E” EMF or volts
Electrical Power
can be transformed from potential energy to kinetic or electrical to mechanical the rate of doing work measured in watts
Uses for alternating current
power transmission and distribution residential, commercial and industrial power
Alternating current sources
hydroelectric dam gas powered alternator automotive alternator electric investor
Magnetic Flux
the entire magnetic field surrounding a magnet
Sine wave
when a conductor in an alternating current generator passes completely passes completely by a north and South Pole of the generator and the value of the voltage is plotted on a graph
RMS
 usable power you are getting out of it
 root mean square
 Equivilent production of heat in a resistive load of a dc current.
Cycles
sine wave starts from 0 volts, reaches a peak at 90* of rotation in the positive direction and drops back down to 0 volts at 180*. It then goes to a peak in the negative direction at 270* and then returns to 0 volts at 360* of rotation
Capacitors
stores the energy until it’s needed (car battery)
Ohm’s Law
“E” stands to EMF (volts) “I” stands for current (amps) “R” stands for resistance (ohms)
Factors affecting resistance
materials cross sectional area length of conductor temperature
Factors affecting Inductance
material frequency amp turns (number of wraps of wire around the coil
Capacitance
same as a hydraulic accumulator two conductors separated by an insulators form a capacitor a capacitor stores electrical energy in an electrostatic field.
Inductance

Series Circuit Math

Electron Flow
Current flow from a negatively charged body to a positively charged body
Parallel Circuit Math

Parallel Circuits
 parallel or divided circuit where the current can flow to the one branch and back or to the other branches but only one at a time
 the more resistors you add, the less resistance the circuit has which allows the current to increase
 the total voltage of the circuit will be used up as it goes throw each branch and comes back to the beginning.
Magnetic pole attraction and repulsion
earth’s north pole and a magnet’s north pole are opposite polarity.