Physics > Alternating Current > 3.0 Some important terms
Alternating Current
1.0 Introduction
2.0 Alternating current and alternating voltage
2.1 Instantaneous current and voltage
2.2 Mean or average current and voltage
2.3 Root mean square current and voltage
2.4 Form factor
3.0 Some important terms
4.0 Circuit element in AC circuit
4.1 Pure resistor circuit
4.2 Pure inductor circuit
4.3 Pure capacitor circuit
4.4 Series $L-R$ circuit
4.5 Series $C-R$ circuit
4.6 Series $L-C-R$ circuit
4.7 Resonance series $L-C-R$ circuit
4.8 Quality factor
4.9 Summary
5.0 Power in AC circuit
3.1 Impedance
2.2 Mean or average current and voltage
2.3 Root mean square current and voltage
2.4 Form factor
4.2 Pure inductor circuit
4.3 Pure capacitor circuit
4.4 Series $L-R$ circuit
4.5 Series $C-R$ circuit
4.6 Series $L-C-R$ circuit
4.7 Resonance series $L-C-R$ circuit
4.8 Quality factor
4.9 Summary
The ratio of the effective voltage to the effective current is defined as the impedance $z$ of the circuit.
Its unit is ohm.
Impedance triangle
It is a right angled triangle, whose base represents ohmic resistance $(R)$, perpendicular represents reactance $\left( {{X_L} - {X_C}} \right)$ and hypotenuse represents impedance $(Z)$ of the series $LCR$ circuit as shown in figure.
Mathematically, impedance is given by, $$Z = \sqrt {{R^2} + {{\left( {{X_L} - {X_C}} \right)}^2}} $$ and $$\tan \phi = \left( {\frac{{{X_L} - {X_C}}}{R}} \right)$$
