Test Review Flashcards
Inductors always _______ a change in current.
Oppose
When current flows through a conductor, what is created?
Magnetic field
What are the important factors concerning electromagnetic induction?
- a conductor
- relative motion
- magnetic field
An induced voltage or current _______ the motion that causes it.
Opposes
Lenz’s Law
What is the greatest advantage of AC?
It can be transformed
The _______ must be found when a sine wave AC voltage is changed into DC with a rectifier?
Average
What is the formula to find RMS value?
RMS = peak * .707
Resistive loads are characterized by the fact that they…
- produce heat
- voltage and current are in phase
A sine wave contains _______ degrees.
360
What is a line that indicates both magnitude and direction?
Vector
What is the formula for instantaneous voltage?
E (isnt) = E(max) * sin(theta)
What three factors determine the amount of voltage induced?
- number of turns of a wire
- strength of magnetic flux (flux density)
- speed of cutting action
Each complete waveform of 360 degrees is called a _______.
Cycle
What is the sum of all angles of a triangle?
180 degrees
What is the unit of measurement for inductance?
Henrys (H)
The amount of inductance on a coil is determined by what two things?
- space between the windings
- physical properties and construction
What is the most common of all AC waveforms?
Sine wave
The _______ of the induced voltage can also be changed by reversing the _______ of the magnetic field.
Polarity; polarity
What does RMS stand for?
Root mean square
What is the formula to solve for RMS value?
RMS = peak * .707
What is a cycle?
A complete waveform