2. Electricity Flashcards
the study of stationary electric charges
Electrostatics
the study of electric charges in motion
Electrodynamics
can be created by contact, friction, or induction
Electrification
is due to the movement of negative electric charge
Electrification
the smallest unit of electric charge is the _____
electron
the fundamental unit of electric charge is _____
coulomb (C)
1 C = ____ electron charges
6.3x10^18 electron charges
unlike charges attract; like charges repel
Electrostatic Laws
The electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance between them
Coulombs’ Law
Unit of Force
N (Newton)
Unit of Charges
Coulomb (C)
Electric Potential is sometimes called
voltage
the unit of electrical potential is the
volt (V)
is potential energy/ unit of charge, or a joule/coulomb (J/C)
volt
flow of electrons in conductor (Electricity)
Electric Current
measured in amperes (A)
Electric Current
is proportional to the number of electrons flowing in the electric circuit
ampere
is equal to an electric charge of 1 C flowing through a conductor each second
one ampere,
1 A = 1 C/s
2 TYPES OF CURRENT
- DC
- AC
Electrons flowing only in one direction
DC
Electrons flowing alternately in opposite direction
AC
is measure in ohms (Ω)
Electric resistance
is a passive two terminal electrical component that implements electrical resistance as a circuit element
Resistor
in electronics circuits, it is often used to limit current flow, to adjust signal levels, bias active elements, and terminate transmission lines among other uses
Resistor
is any substance through which electrons flows easily
Conductors
Copper (Cu), Aluminum (Al), water
Conductors
is any material that does not allow electron flow
Insulators
glass, clay other earthlike material, rubber
Insulators
is a material that under some conditions behave as an insulator and in other conditions behaves as a conductor
Semiconductors
In ______ , _______ demonstrated semi conduction
1946,
William Shockley
Silicon (Si) - 14, Germanium (Ge) - 32
Semiconductors
is the property of some materials to exhibit no resistance below a critical temperature (Tc)
Superconductivity
Niobium (41), Titanium (22)
Superconductivity
Superconductivity Discovered in _____, commercially available in _____
1911,
1960s
when the resistance is controlled and the conductor is made into a closed path, the result is an
Electric Current
the voltage across the total circuit or any portion of the circuit is equal to the current times the resistance
Ohm’s Law
Ohm’s Law
V = IR
all circuit elements are connected in a line along the same conductor
Series circuit
contains elements that are connected at their ends rather than lie in a line along a conductor
Parallel circuit
RULES FOR SERIES CIRCUITS
- The total resistance is equal to the sum of the individual resistances (RT = R1 + R2 + R3)
- The current through each circuit elements is the same and is equal to the total circuit current voltage (IT = I1 = I2 = I3)
- The sum of the voltages across each circuit element is equal to the total circuit voltage (VT = V1 + V2 + V3)
RULES FOR PARALLEL CIRCUITS
- The sum of the currents through each circuit element is equal to the total circuit current (IT = I1 + I2 + I3)
- The voltage across each circuit element is the same and is equal to the total circuit voltage (VT = V1 = V2 = V3)
- The total resistance is the inverse of the sum of the reciprocals of each individual resistance (1/RT = 1/R1 + 1/R2 + 1/R3)
is measured in watts (W)
Electric Power
is equal to 1 A current flowing through an electric potential of 1 V
one watt,
1 W = 1 A + 1 V
in an electric power system, is any abnormal electric current
Electric Fault (Fault or Fault Current)
is any failure that allows unintended connection of power circuit conductors with the earth
Ground Fault (Earth Fault)
provides an alternate path for electricity to follow, rather than going through a person
Electrical Grounding
happens when current passes through the body
Electrical Shock
refers to the injury or lethal dose of electrical energy
Electrocution
Electrical fires may be caused by excessive resistance that generates heat from any of the following:
- Too much current running through wiring where overcurrent protection fails or does not exist
- Faulty electrical outlets resulting in poor contact or arcing
- Poor wiring connections and old wiring that is damaged and cannot support the load
can occur when electricity ignites a flammable gas or combustible dust mixture in the air. Ignition from a short circuit or static charge is possible
Explosion
is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected
Circuit breaker
a device that shuts off power instantly if there is a problem
Ground Fault Circuit Interrupter (GCFI)
GFCI
Ground Fault Circuit Interrupter
Its basic function is to interrupt current flow after a fault is detected
Circuit breaker