3.13 AC theory Flashcards
(18 cards)
what are the two main characteristics that distinguished AC from DC
The amount (size) of both the voltage and current changes with time.
The direction (polarity) of both the voltage and current changes with time.
what is the phase of aperiodic function a measure of
the fraction of the cycle that has been completed at a particular point on the X-axis
what is the initial angle of a sinusoidal function called
'’phase offset’’
what does the phase difference describe
the relative displacement between two points in a cycle of two waveforms with the same frequency
what is the period of a wave
the time taken to preform one complete cycle
what is the frequency of a wave
the number of complete cycles per second
what is frequency also defined as
the reciprocal of the period or cycle time
what is the peak value of the voltage or current in an ac waveform called
the amplitude
what is the root mean square
the value which, when applied to a resistance R, will produce the same power output as an equivalent DC current or DC voltage.
what does the peak-to-peak value mean
twice the peak value
describe square waveform
a waveform that rises quickly to a particular amplitude, remains constant for a time period and drops fast at the end
describe triangular waveform
bi-directional non-sinusoidal waveforms that oscillate between a positive and a negative peak value
what is the difference between sawtooth and triangular waveforms
a sawtooth wave generator, the rise time may be much higher than its fall time or vice versa
in the multi phase system what is the displacement from one coil to another
120 degree
what is single phase power
a two-wire alternating current (AC) power circuit
what is the difference between single phase and three phase
a three phase power supply better accommodates higher loads
how are the phases on a three phase system identified on an aircraft
A - B - C.
