Microsecond

From Wikipedia, the free encyclopedia
Jump to: navigation, search

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.

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[edit]

  • 1 microsecond (1 μs) – cycle time for frequency 1×106 hertz (1 MHz), the inverse unit. This corresponds to radio wavelength 300 m (AM mediumwave band), as can be calculated by multiplying 1 µs by the speed of light (approximately 300×106 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.[1]
  • 3.33564095 microseconds – the time taken by light to travel one kilometer in a vacuum
  • 5.4 microseconds – the time taken by light to travel one mile in a vacuum
  • 10 microseconds (μs) – cycle time for frequency 100 kHz, radio wavelength 3 km
  • 17 microseconds: net amount per year that the length of the day lengthens, largely due to tidal acceleration.[citation needed]
  • 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[2]
  • 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 [3]
  • 100 microseconds (0.1 ms) – cycle time for frequency 10 kHz
  • 125 microseconds – sampling interval for telephone audio (8000 samples/s)
  • 240 microseconds – half-life of copernicium-277
  • 250 microseconds – cycle time for highest tone in telephone audio (4 kHz)[citation needed]

For reference[edit]

  • The average human eye blink takes 350,000 microseconds (just over 1/3 of one second).
  • The average human finger click 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.

See also[edit]

References[edit]

  1. ^ Buis, Alan (January 10, 2005). "NASA Details Earthquake Effects on the Earth". NASA. Retrieved June 29, 2011. 
  2. ^ Richard Pogge. "GPS and Relativity". Retrieved 2011-10-01. 
  3. ^ Intel Solid State Drive Product Specification http://www.intel.com/content/www/us/en/solid-state-drives/ssd-dc-s3500-spec.html

External links[edit]