Harman Patil (Editor)

Microsecond

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Microsecond

A microsecond is an SI unit of time equal to one millionth (0.000001 or 10−6 or 1/1,000,000) of a second. Its symbol is μs. One microsecond is to one second as one second is to 11.574 days.

Contents

A microsecond is equal to 1000 nanoseconds or 1/1,000 milliseconds. Because the next SI prefix is 1000 times larger, measurements of 10−5 and 10−4 seconds are typically expressed as tens or hundreds of microseconds. A microsecond of sound signal sample (44.1 kHz, 2 channel, 24 bit, WAV) is typically stored on 4 µm of CD, 2 bits per µs per 4 µm.

Examples

  • 1 microsecond (1 μs) – cycle time for frequency 1×106 hertz (1 MHz), the inverse unit. This corresponds to radio wavelength 300 m (AM medium wave band), as can be calculated by multiplying 1 µs by the speed of light (approximately 3.00×108 m/s) to determine the distance travelled.
  • 1 microsecond – the length of time of a high-speed, commercial strobe light flash (see air-gap flash).
  • 1.8 microseconds – the amount of time subtracted from the Earth's day as a result of the 2011 Japanese earthquake.
  • 2 microseconds – the lifetime of a muonium particle
  • 2.68 microseconds – the amount of time subtracted from the Earth's day as a result of the 2004 Indian Ocean earthquake.
  • 3.33564095 microseconds – the time taken by light to travel one kilometer in a vacuum
  • 4.63 microseconds – a fifth (a 60th of a 60th of a 60th of a second)
  • 5.4 microseconds – the time taken by light to travel one mile in a vacuum (or radio waves point-to-point in a near vacuum)
  • 8.01 microseconds - the time taken by light to travel one mile in typical single mode fiber optic cable
  • 10 microseconds (μs) – cycle time for frequency 100 kHz, radio wavelength 3 km
  • 18 microseconds – net amount per year that the length of the day lengthens, largely due to tidal acceleration.
  • 20.8 microseconds – sampling interval for digital audio with 48000 samples/s
  • 22.7 microseconds – sampling interval for CD audio (44100 samples/s)
  • 38 microseconds – discrepancy in GPS satellite time per day (compensated by clock speed) due to relativity
  • 50 microseconds – cycle time for highest human-audible tone (20 kHz)
  • 50 microseconds to read – the access latency for a modern solid state drive which holds non-volatile computer data
  • 100 microseconds (0.1 ms) – cycle time for frequency 10 kHz
  • 125 microseconds – sampling interval for telephone audio (8000 samples/s)
  • 164 microseconds - half-life of polonium-214
  • 240 microseconds – half-life of copernicium-277
  • 250 microseconds – cycle time for highest tone in telephone audio (4 kHz)
  • 277.8 microseconds – a fourth (a 60th of a 60th of a second), used in astronomical calculations by al-Biruni and Roger Bacon in 1000 and 1267 AD, respectively.
  • 489.67 microseconds - time for light at a 1550 nm frequency to travel 100 km in a singlemode fiber optic cable (where speed of light is approximately 200 million meters per second due to internal reflectance).

    • For reference

  • The average human eye blink takes 350,000 microseconds (just over 1/3 of one second).
  • The average human finger snap takes 150,000 microseconds (just over 1/7 of one second).
  • A camera flash illuminates for 1000 microseconds.
  • Standard camera shutter speed opens the shutter for 4000 microseconds or 4 milliseconds.

    • References

    Microsecond Wikipedia
    (Text) CC BY-SA