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Module 4. Electronic fundamentals

The output of a tachogenerator should be

  • exponential.
  • linear.
  • sinusoidal.

Explanation

An AC tachogenerator is excited from an AC reference, so its output is an alternating waveform; the amplitude varies with shaft speed but the waveform itself is a sine wave at the reference frequency. The output is therefore sinusoidal.

udreacc asking:

in the question it is not mentioned it is referring to AC

Community Comments (1)

C
carlosmd Posts: 2 08.07.2026 / 04:15
Why else would the cockpit indicator run off it as a synchronous motor if the tacho was not making AC? The aircraft tachogenerator is a 3 phase permanent magnet unit, so the output is a sinusoidal AC voltage whose frequency tracks the rpm, that is why it is sinusoidal even though the stem never says AC. Linear only describes voltage against speed, not the waveform, so it does not apply here.

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