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Electromagnetic induction
voltage produced when lines of magnetic flux are cut by a conductor
Exponential curve
natural curve that is the rate at which current can rise or fall in an inductor
How many time constants are in the exponential curve
5 time constants
The exponential curve is divided into what units
time constants
Henry abbreviation
H
What is the basic unit of inductance
The Henry
Inductance is represented by what letter
L
Lenz’s law
law that explains relationship of movement, voltage polarity, and magnetic field polarity as they relate to magnetic induction
MOV stands for
metal oxide varistor
MOV
semiconductor device that changes its resistance in accord with voltage applied across it
R-L time cosntant
formula to determine rate of rise or fall of current in an inductive circuit
Voltage spike
momentary increase of voltage lasting 2 ns or less
When do voltage spikes usually occur in a circuit
When the circuit opens
Weber (Wb)
measure of magnetic lines of flux
1 Wb equals
100 million lines of flux
What is created when a conductor is moved through a magnetic field
a voltage is induced in the conductor
What determines induced voltage polarity
direction of relative motion
polarity of the magnet
For electron current flow left hand or right hand is used
left hand
Important factors in electromagnetic induction
conductor
magnetic field
relative motion
What 3 factors affect the amount of induced voltage
number of turns of wire
strength of the magnetic field
speed of cutting action
What happens to induced voltage if the relative motion, number of turns of wire, speed, or strength of magnetic field increases
induced voltage increases
Lenz’s law states that an induced voltage will
oppose the motion that causes it
Induced voltage is _ to rate of change of current
proportional
At what point of the exponential curve will an inductor reach its full value
it won’t, it will get close and at that point it will be considered to be complete
What determines amount of inductance
physical properties and construction of the coil
Inductance formula
L = 4piN2muA/l
R-L time constant formula
T = L/R
Induced voltage spike formula
EMF = - L (delta i/delta t)
DIodes can only be used in what circuits
DC
What determines magnetic polarity when current flows through a conductor
direction of current flow
What determines strength of magnetic field when current flows through a conductor
amount of current
Note 
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