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AF Oscillator (Audio Frequency Oscillator)

 

AF Oscillator (Audio Frequency Oscillator)

What is an AF Oscillator?

An AF oscillator (Audio Frequency Oscillator) is an electronic circuit that generates alternating current (AC) signals in the audio frequency range.

Frequency range: 20 Hz to 20 kHz (human hearing range)

It produces waveforms such as sine waves, square waves, or triangle waves.

The oscillator converts DC power into a repeating AC signal using feedback.

How It Works

  1. A circuit amplifies a signal
  2. Part of the output is fed back to the input
  3. If feedback is in phase, oscillations continue

This is called positive feedback.

Mathematical Representation

General waveform equation:

v(t) = A sin(ωt + φ)

  • A = amplitude
  • ω = 2Ï€f
  • f = frequency (Hz)
  • t = time
  • φ = phase

Types of AF Oscillators

1. RC Oscillator

Uses resistors and capacitors.

f ≈ 1 / (2Ï€RC)

Used in audio tone generators.

2. LC Oscillator

Uses inductors and capacitors.

f = 1 / (2Ï€√LC)

3. Wien Bridge Oscillator

Produces clean sine waves and is widely used in lab equipment.

Applications

  • Audio signal generators
  • Radio testing
  • Speaker testing
  • Sound equipment calibration
  • Musical instruments and synthesizers

An AF oscillator is a circuit that continuously reinforces a signal to produce steady sound-frequency waves.

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