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WorksheetsM3 Cat A M3.13 AC Theory
Total questions: 16
Worksheet time: 8mins
What is the main characteristic that distinguishes AC from DC?
In AC the amount (size) of voltage remains constant.
In AC the direction (polarity) of current remains constant.
In AC the amount (size) of both voltage and current changes with time.
In AC the direction (polarity) of both voltage and current changes with time.
Which statement accurately describes common AC?
The changes in voltage and current never repeat.
The average voltage and current are always positive.
The voltage and current vary sinusoidally with time.
The current remains constant over time.
What does the term "phase difference" refer to?
The difference in size between voltage and current.
The time it takes for a wave to complete one cycle.
The relative displacement between two points in a cycle of two waveforms.
The amount of current flowing through a circuit.
What is the unit of frequency?
Volt (V)
Watt (W)
Seconds (s)
What is the amplitude of an AC waveform?
The average value of voltage or current over a full cycle.
The peak value of voltage or current.
The instantaneous value of voltage or current.
The root mean square value of voltage or current.
What is the instantaneous value of an alternating voltage or current?
The value at a particular instant, which may vary between zero and the peak value.
How is the average voltage over one half cycle of an AC waveform calculated?
By dividing the peak voltage by π.
By summing equally spaced instantaneous values of the half cycle and dividing by the number of mid-ordinates.
By taking the square root of the peak voltage.
By finding the difference between peak and peak-to-peak voltage
What does RMS value represent in AC voltage or current?
The maximum value of voltage or current.
The average value of voltage or current over a full cycle.
The difference between peak and peak-to-peak voltage.
The value which, when applied to a resistance, will produce the same power output as an equivalent DC current or DC voltage.
What defines a square waveform?
It rises quickly to a particular amplitude, remains constant for a time period, and drops fast at the end.
It is a waveform with a symmetrical shape and equal rise and fall times.
It oscillates between positive and negative peak values.
It has a steady rate of change of voltage over each half cycle.
What is the characteristic duty cycle of a square waveform?
10%
What distinguishes a rectangular waveform from a square waveform?
What characteristic describes a sawtooth waveform?
Its rise time may be much higher than its fall time or vice versa.
It oscillates between positive and negative peak values.
It rises quickly to a particular amplitude, remains constant for a time period, and drops fast at the end.
It has a steady rate of change of voltage over each half cycle.
What distinguishes multi-phase systems from single-phase systems?
Multi-phase systems have a higher voltage output.
Single-phase systems use more wires than multi-phase systems.
Multi-phase systems have only one power wire and one neutral wire
Multi-phase systems have coils displaced from each other by specific angles.
In a three-phase system, how are the coils mounted?
What is the main difference between single-phase and three-phase power supplies?
Single-phase power supplies have a higher voltage output.
Single-phase power supplies have more wires than three-phase power supplies.
Single-phase power supplies are used for lighting or heating loads, while three-phase power supplies accommodate higher loads.
Single-phase power supplies are typically used in industrial facilities, while three-phase power supplies are used in residential homes.
How are phases identified in a three-phase system on aircraft?
Select all correct answers
RED, YELLOW, and BLUE.
A, B, and C
1, 2, and 3
X, Y, and Z
α,Φ, and θ
