Oscillator comes from the Latin term “oscillare,” meaning to swing or rock.

An electronic oscillator is a circuit that produces a repetitive signal by utilizing a very sensitive amplifier whose output is attached to an electronic filter—or to a quartz crystal—which is fed back to the input of the amplifier at the same rate, creating a feedback loop that produces positive feedback, allowing the signal to regenerate and sustain itself.

Common oscillator waveforms are:

  • Saw Wave – shaped like the teeth on a saw blade, this produces a very common sharp, biting tone.
  • Square Wave – looks like a (near) perfect square, produces a reedy, hollow sound.
  • Pulse Wave – a variation on the square wave, the pulse wave is half as wide as a square wave, and has the unique ability to have its width modulated (called ‘Pulse Width Modulation’).
  • Triangle Wave – unsurprisingly shaped like a triangle, this sounds somewhere in between a saw wave and a sine wave.
  • Sine Wave – a smooth rising and falling shape (like a horizontal ‘S’), this produces a mild, soft tone.