# Electronics Bible/Inductor

Inductor is an electronics device made from a coil of many circular loops that can store energy as Magnetic field

## Inductance

Inductance represents inductor's capability to store energy as Magnetic field . Inductor has a symbol ${\displaystyle L}$ and measured in unit Henry ${\displaystyle H}$

${\displaystyle L={\frac {B}{i}}}$

Inductor can be made from a coil of many circular loops that has inductance

${\displaystyle L=\mu i{\frac {Nl}{A}}}$

From above

${\displaystyle L={\frac {B}{i}}=\mu i{\frac {Nl}{A}}}$
${\displaystyle \mu ={\frac {B}{i^{2}}}{\frac {A}{Nl}}}$

## Electricity response of inductor

### Inductor and DC electricity

Electric charge

${\displaystyle B=LI}$ . Ampere's law

Capacitance

${\displaystyle I={\frac {B}{L}}}$

Voltage

${\displaystyle L={\frac {B}{I}}}$

### Inductor and AC electricity

Voltage

${\displaystyle v(t)=L{\frac {d}{dt}}i(t)}$

Current

${\displaystyle i(t)={\frac {1}{L}}\int v(t)dt}$

Power

${\displaystyle p(t)={\frac {1}{2}}Li^{2}(t)}$

Impedance

${\displaystyle Z={\frac {v(t)}{i(t)}}=R_{L}+X_{L}=R+\omega L\angle 90=R+j\omega L=R+sL}$

Reactance

${\displaystyle X_{L}=\omega L\angle 90=j\omega L=sL}$

Phase angle

${\displaystyle Tan\theta =\omega T}$

Time constant

${\displaystyle T={\frac {L}{R}}}$