Level 3 Engineering Principles - AC Circuits Info and Equations
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Sinusoidal<br />
Square / Rectangular<br />
Saw Tooth<br />
Triangular<br />
LEVEL 3 ENGINEERING PRINCIPLES - <strong>AC</strong> CIRCUITS INFORMATION AND EQUATIONS<br />
Waveform Characteristics<br />
Waveform<br />
Characteristics<br />
A = amplitude / peak value<br />
P2P = peak to peak value<br />
T = periodic time (s)<br />
f = frequency (Hz) = 1/T<br />
O = offset<br />
φ = phase angle<br />
(degrees / rads)<br />
<strong>AC</strong> Waveform Average <strong>and</strong> RMS Values<br />
Waveform Average Root Mean Square<br />
(RMS)<br />
Ave = 2 × Peak Value RMS<br />
π<br />
Peak Value<br />
=<br />
√2<br />
Ave = Peak Value<br />
RMS = Peak Value<br />
Ave =<br />
Peak Value<br />
2<br />
Peak Value<br />
RMS =<br />
√3<br />
Ave =<br />
Peak Value<br />
2<br />
Peak Value<br />
RMS =<br />
√3
Reactance <strong>and</strong> Impedance <strong>Equations</strong><br />
Subject Equation Variables <strong>and</strong> Units<br />
Capacitative Reactance<br />
(Capacitor)<br />
X C = 1<br />
2πfC<br />
Inductive Reactance<br />
(Inductor)<br />
X L = 2πfL<br />
XC = capacitative reactance<br />
in Ohms (Ω)<br />
f = supply frequency in<br />
Hertz (Hz)<br />
C = capacitance in Farads (F)<br />
Passive Resistance - <strong>AC</strong><br />
(Resistor)<br />
Total Impedance<br />
(Resistor <strong>and</strong> Capacitor<br />
in Series)<br />
Total Impedance<br />
(Resistor <strong>and</strong> Inductor<br />
in Series)<br />
R = V RMS<br />
I RMS<br />
Z = √X C 2 + R 2<br />
ϕ = tan −1 ( −X C<br />
R )<br />
Z = √X L 2 + R 2<br />
ϕ = tan −1 ( X L<br />
R )<br />
XL = inductive reactance<br />
in Ohms (Ω)<br />
L = inductance in Henries (H)<br />
R = resistance in Ohms (Ω)<br />
VRMS = root mean square<br />
voltage in Volts (V)<br />
IRMS = root mean square<br />
current in Amps (A)<br />
Z = total impedance in<br />
Ohms (Ω)<br />
φ =phase angle in degrees /<br />
radians<br />
Total Impedance<br />
(Resistor, Capacitor<br />
<strong>and</strong> Inductor in Series)<br />
Z = √(X L − X C ) 2 + R 2<br />
ϕ = tan −1 ( X L − X C<br />
)<br />
R