Practical Electronics/Basic Theory/General Formulae

Charge
Charge refers to quantities of Electric Charge of an object
 * 1 C = Number of Electrons e

Voltage
Voltage is defined as Work done on a Charge
 * $$Q = \int W dt$$

Current
Current is defined as ratio of Charge over Time
 * $$I = \frac{Q}{t}$$
 * I, Current
 * Q, Charge
 * t, Time
 * $$1 A = \frac{1 C}{1 s}$$

Resistance

 * $$R = \frac{V}{I}$$
 * R, Resistance
 * V, Voltage
 * I, Current

Conductance

 * $$G = \frac{1}{R}$$
 * $$G = \frac{I}{V}$$
 * G, Conductance
 * R, Resistance
 * I, Current
 * V, Volatge

Reactance

 * X = ± j ω T
 * X, Reactance
 * ω, Angular of Frequency
 * T, Time Constant

Impedance

 * Z = R + X
 * Z, Impedance
 * R, Resistance
 * X, Reactance

Power Loss

 * P R = I V = $$I^2 R$$ = $$\frac{V^2}{R}$$

Power Delivered

 * $$P = P_V - P_R = VI - I^2R = VI - \frac{V^2}{R}$$

Power Stored

 * $$P_C = \frac{1}{2} C V^2$$
 * $$P_L = \frac{1}{2} L I^2$$