WEEK 7 NOTES Flashcards
What is an inductor? (L)
An element in a circuit which opposes sudden changes in the current
How do inductors work?
They store kinetic energy of of moving electrons as energy in an electromagnetic field which is released in suitable conditions
What can inductors (L) also be known as?
Coils or chokes.
What happens when current is increased through an inductor?
It drops a voltage opposing the current flow, this is known as back EMF. The inductor charges and becomes a power load
What happens when current is decreased through an inductor?
It drops a voltage aiding the direction of current flow and acts as a power source to the rest of the circuit.
The inductor is discharging as the energy its storing is decreasing
What is inductance?
The ratio of voltage to the rate of change of current
What is self-inductance?
When the EMF is induced in the same circuit in which the current is changing
Where does inductance come from?
It is an electrical property induced from the magnetic field
What is the unit for inductance?
H - Henry
What are some factors that affect inductance?
The more turns of a wire the higher the inductance
The larger the cross-sectional area of the wire the larger the inductance
If there is a magnetic core the magnetic field will be stronger and therefore a higher inductance
Short thick coils have a larger inductance than long thin coils
What is mutual induction?
When two coils are connected adjacently and the EMF is induced
As soon as the switch is closed in an RL circuit what does the current through a resistor become?
The current increases to its final value.
I=V/R
What happens when a switch opens in an RL circuit?
The current decreases, the magnetic field decreases and the EMF increases in the direction that keeps current flowing in the same direction as applied voltage
