Basic AC Circuit Formulas

Basic AC Circuit Formulas

Basics:

v=V_m\sin{\omega t}v = value of alternating voltage at time t (called instantaneous value)
Vm = maximum value of alternating voltage
\omega= Angular velocity of the coil
i=I_m\sin{\omega t}i =value of alternating current at time t (called instantaneous value)
Im = maximum value of alternating current
\omega = Angular velocity of the coil
T=\frac{1}{f}T = Time period in second
f = frequency in Hz
\omega={2 \pi f}\omega= Angular frequency
f = frequency
I_{av}=\frac{2 I_m}{\pi} =0.637I_m

V_{av}=\frac{2 V_m}{\pi}=0.637V_m
Iav = Average value of Current
Im= Maximum value of Current
I_{rms}=\frac{ I_m}{\sqrt{2}} =0.707I_m

V_{rms}=\frac{ V_m}{\sqrt{2}}=0.707V_m
Irms = RMS value of Current
Im= Maximum value of Current
\text{Form factor}= \frac{\text{rms value}}{\text{average value}}For an alternating voltage or current varying sinusoidally, its value is 1.11
\text{Peak factor or Crest Factor}= \frac{\text{maximum value}}{\text{rms value}}For an alternating voltage or current varying sinusoidally, its value is 1.414
X_{L}={2\pi f L}={\omega L} XL=Inductive Reactance
f= frequency
L= Inductance
X_{C}=\frac{ 1}{2\pi f C}= \frac{ 1}{ \omega C}XC=Capacitive Reactance
f= frequency
C= Capacitance