# 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

${\displaystyle Q=\int Wdt}$

## Current

Current is defined as ratio of Charge over Time

${\displaystyle I={\frac {Q}{t}}}$
I , Current
Q , Charge
t , Time
${\displaystyle 1A={\frac {1C}{1s}}}$

## Resistance

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

## Conductance

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

## Reactance

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

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

## Power

### Power Loss

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

### Power Delivered

${\displaystyle P=P_{V}-P_{R}=VI-I^{2}R=VI-{\frac {V^{2}}{R}}}$

### Power Stored

${\displaystyle P_{C}={\frac {1}{2}}CV^{2}}$
${\displaystyle P_{L}={\frac {1}{2}}LI^{2}}$