# Fundamental Physics/Electronics/Electronics Oscillator

## Electronics Oscillator

Electronics Oscillator is an electronics device that generates oscillation .

1. Passive oscillator
2. Active oscillator
3. Variation

## Passive oscillator

Passive oscillator can be constructed from

### LC resonance tank circuit

${\displaystyle i(t)=Asin\omega t}$
${\displaystyle \omega ={\sqrt {\frac {1}{LC}}}=2\pi f}$
${\displaystyle f={\frac {1}{2\pi }}{\sqrt {\frac {1}{LC}}}}$

### RC phase shift

${\displaystyle i(t)=Asin\omega t}$
${\displaystyle \omega ={\frac {1}{RC}}{\frac {1}{Tan\theta }}=2\pi f}$
${\displaystyle f={\frac {1}{2\pi }}{\frac {1}{RC}}{\frac {1}{Tan\theta }}}$

## Active oscillator

Active oscillator can be constructed from class A Inverting amplifier with LC tune tank in the feedback . Class A Inverting amplifier has inverting amplification factor equals to -1

### Class A Inverting amplifier + LC tune tank in the feedback

${\displaystyle i(t)=Asin\omega t}$
${\displaystyle \omega ={\sqrt {\frac {1}{LC}}}=2\pi f}$
${\displaystyle f={\frac {1}{2\pi }}{\sqrt {\frac {1}{LC}}}}$

### Class A Inverting amplifier + 3 stages of RC phase shift each has a phase shift of 60o in the feedback

${\displaystyle i(t)=Asin\omega t}$
${\displaystyle \omega ={\frac {1}{RC}}{\frac {1}{Tan\theta }}=2\pi f}$
${\displaystyle f={\frac {1}{2\pi }}{\frac {1}{RC}}{\frac {1}{Tan\theta }}}$