| Quantity | Formula | Unit | |----------|---------|------| | Ohm’s Law | ( V = I R ) | Volt, Amp, Ohm | | Resistors series | ( R_eq = R_1 + R_2 + \dots ) | Ohm | | Resistors parallel | ( \frac1R_eq = \frac1R_1 + \frac1R_2 + \dots ) | Ohm | | Inductive reactance | ( X_L = 2\pi f L ) | Ohm | | Capacitive reactance | ( X_C = \frac12\pi f C ) | Ohm | | Impedance (series RL) | ( Z = \sqrtR^2 + X_L^2 ) | Ohm | | Phase angle (RL) | ( \phi = \arctan(X_L / R) ) | degrees/rad | | Power factor | ( pf = \cos\phi ) | unitless | | Active power | ( P = V I \cos\phi ) | Watt | | Reactive power | ( Q = V I \sin\phi ) | VAR | | Apparent power | ( S = V I ) | VA |
A heater runs on $220V$ and draws $5A$. How much energy does it use in 2 hours? elektroteknika 1 ushtrime full