AC Circuits

Question 1

How is an AC waveform generated?

Answer 1

A magnetic field rotates from 0° > 90° > 180° > 270° > 0° etc. if placed on an xy graph
The north pole being in the x+ region is what creates the positive half of the wave in an AC waveform (0° > 180°)
The south pole being in the x+ region creates the other, negative half of the wave (180° > 360°)

Question 2

What is frequency? What is it measured in?

Answer 2

The cycles of an AC waveform produced per second
Hz (hertz)

Question 3

What is the relationship between voltage and current like in a purely resistive circuit? What about purely inductive and capacitive circuits?

Answer 3

Purely resistive - in phase (V reaches max. value when I reaches max. value)
Purely inductive/capacitive - V and I reach max. values at different times

Question 4

What type of diagram can be used to represent sine waves? What exactly does this type of diagram show?

Answer 4

Phasor diagram
The relationship between V and I and the angle between them

Question 5

What is resistance to current called in a pure inductive coil? What is it called in a capacitor? What are their symbols?

Answer 5

Inductive reactance (XL)
Capacitive reactance (XC)

Question 6

What is the resistance to current in the whole of an RLC circuit called? What is its symbol? What are its leading and lagging (of current) equations?

Answer 6

Impedance (Z)
Z = √(R^2 + (XL - XC)^2) (lagging)
Z = √(R^2 + (XC - XL)^2) (leading)