A.C. Theory, Lvl 1: Lesson #1- Understanding inductance and How it affects a circuit Flashcards by Samantha Bostic (2024)

The direction of induced ? flow through a conductor is determined by the direction of the magnetic field surrounding the conductor and the direction the conductor is traveling through the magnetic field.

Current

Whenever a conductor cuts through magnetic lines of flux, a ? is induced into the conductor.

Voltage

Whenever current flows through a conductor, a ? is created around the conductor.

Magnetic field

When no current flows in a conductor, free electrons move ? , and their magnetic fields cancel.

at random

When current flows in a conductor, a magnetic field is produced. As free electrons move in one direction, their individual magnetic fields ? .

add together

The important factors needed for generation of an induced voltage are a conductor, a magnetic field, and ? .

relative motion

As current flow decreases, the magnetic field surrounding the conductor will ? .

decreases

As the current passing through a coil increases, the magnetic field around the coil will ? .

increases

Whenever an electric current flows through a conductor, a magnetic field is formed ? the conductor.

around

? Law states that an induced voltage or current opposes the motion that causes the induced voltage or current.

Lenzs

Inductors always oppose a change of ? .

current

Counter Electromotive Force is sometimes called back EMF, and CEMF is ? out-of-phase with the applied voltage.

180°

CEMF ? the applied EMF when current is increasing and ? the applied EMF when current is decreasing.

subtracts from / adds to

List factors that work in combination to affect the inductance produced by an inductor.

-Cross sectional area of the core
-Permeability of the core material
-Spacing between the turns

The rate of current change in an inductive circuit can be described as a(n) ? curve.

exponential

How many time constants does it take for current to reach its maximum value in an inductive circuit?

5

At what percentage is the current after one time constant when the circuit is first energized?

63.2% of maximum

The unit of inductance is the ? , and inductance is represented by the letter ? .

henry / L

If a change of one ampere in one second causes one volt to be induced, you have ? of inductance.

one henry

In high frequency applications, ? inductors are used because of eddy current loss and hysteresis loss in the core material.

air core

Cross sectional area of the core = A
Length of the core used = I
Number of turns of wire = N
Permeability of the type of core material used = μ

Inductance will ? with an increase in the cross sectional area of the core.

Increase

Inductance is ? proportional to the length of the core used

inversely

Inductance will ? with an increase in the number of turns of wire.

increase

Inductance is ? proportional to the permeability of the type of core material used

directly

What is the formula for determining the time constant in an inductive circuit?

Given the formula for determining the counter EMF (induced voltage of a coil), drag the variables to the statement they represent.