Inductance And Inductors Flashcards
What is the number of flux linkages when two inductive coils are placed in close proximity at 90 degrees?
0
What is the mutual inductance if two coils of 10mH and 500mH have 90% of the flux transferred from one to the other?
63mH
What is the value of an inductor with 1,000 turns of wire, a cross-sectional area of 0.001m2, a permeability of 0.000001, and a coil length of 0.1m?
10mH
What is the total inductance of three inductors with values 10 mH, 5 mH, and 20 mH connected in parallel?
2.86mH
If the current reaches a maximum of 2A through an inductor in 15 seconds, what is the current after 3 seconds?
1.26A
What is the time constant of an inductor?
L/R
If the rate of change of current is halved, what happens to mutual inductance?
stay the same
Why are the iron cores of most induction coils laminated?
To reduce the effects of eddy currents
When more than two inductors of different inductance are connected in parallel, what is the total inductance?
less than the inductance of the lowest rated inductor
What is the time required for the current in an inductive circuit to reach 63.2% of its maximum value?
63.2% of maximum value
What is the opposition to current flow in an AC inductive circuit with an inductance of 10 mH and a frequency of 1000Hz?
63 ohms
What happens when rotating coil B through 90°?
decrease the EMF induced into B
What is the time constant of an inductor with resistance 5 kΩ and inductance 2mH?
400 ns
What happens to the back EMF in a collapsing field in an inductor when switching off the supply?
can be multiple times bigger than forward EMF
What does an induced current in a coil do?
opposes the EMF producing it
