Ok the first thing that went through my mind when I saw the word Yottawatts was that episode of Seinfeld where Elaine uses the phrase…yadda, yadda, yadda…

But its actually about powers of ten and electrical power (watts). I was researching the amount of solar insolation the earth receives from the sun (174 Petawatts) and ran across this page in WikiPedia full of variations on my namesake.

By the way, Petawatts has nothing to do with my disdain for the sometimes crazy tactics of the animal rights group.

So have a few watts on me:

Yoctowatt (10-24 watt)

Zeptowatt (10-21 watt)

Attowatt (10-18 watt)

Femtowatt (10-15 watt)

  • 2.5 fW – Tech: minimum discernible signal at the antenna terminal

    of a good FM radio


  • 10 fW (-110 dBm) – Tech: approximate lower limit of power reception

    on digital spread-spectrum cell phones

Picowatt (10-12 watt)

  • 1 pW – BioMed: average power consumption of a human cell
  • 2.5 pW – BioMed: Sound intensity per square centimeter for average

    human threshold of hearing at 1000 Hz; 1 phon

    or 0 dB SPL

  • 150 pW – BioMed: Power entering a human eye from a 100 watt lamp 1

    km away

Nanowatt (10-9 watt)

  • 2-15nW – Tech: Power consumption of some PIC Microcontroller chips

    such as the PIC12F683 when in "sleep" mode. (actual consumption

    when sleeping depends on voltage supply used, see data sheet, Electrical

    Characteristics section).

Microwatt (10-6 watt)

Milliwatt (10-3 watt)

  • 5 mW – Tech: laser in a CD-ROM


  • 5-10 mW – Tech: laser in a DVD


  • 100 mW – Tech: laser in a CD-R



1 Watt = 1 amp x

1 volt of electrical power

  • 5 W – Legal: maximum power output of a CB

    or hand-held radio transmitter

  • 20-40 W – BioMed: approximate power consumption of the human brain
  • 30-40 W – Tech: the power of the typical household tube light
  • 60 W – Tech: the power of the typical household light


  • 82 W – Tech: peak power consumption of Pentium

    4 CPU

  • 100 W – BioMed: approximate average power used by the human


  • 120 W – Tech: power output of 1 m2 solar

    panel in full sunlight

  • 253 W (2,215 kWh/year)

    Geo: per capita average power use of the world in 2001

  • 290 W – Units: approximately 1000 BTU/hour
  • 300-400 W – Tech: typical PC

    power supply

  • 400 W – Tech: legal limit of power output of an amateur

    radio station in the United


  • 500 W – BioMed: power output of a person working hard physically
  • 745.7 W – Units: 1 horsepower
  • 750 W – Astro: the amount of sunshine falling on a square metre of

    the Earth’s surface on a clear day

  • 900 W – BioMed: power output of a healthy human (non-athlete)

    averaged over the first 6s of a 30s cycle sprint. [1]

Kilowatt (103 watt)

  • 1.366 kW – Astro: power received from the Sun

    at the Earth‘s

    orbit by one

    square metre

  • 1.39 kW (12.2 MWh/year) – Geo: per capita average power use in the U.S.

    in 2003

  • 1.5 kW – Tech: legal limit of power output of an amateur

    radio station in the United


  • up to 2 kW – BioMed: approximate short time power output of

    sprinting professional cyclists

  • 1 kW to 2 kW – Tech: heat output of a domestic electric kettle.
  • 3.3-6.6 kW – Eco: average photosynthetic

    power output per square

    kilometer of ocean


  • 30 kW – power generated by the four motors of GEN H-4 one man helicopter
  • 16-32 kW – Eco: average photosynthetic power output per square

    kilometer of land


  • 50 kW to 100 kW – Tech: ERP

    of clear

    channel AM

  • 40 kW to 200 kW – Tech: approximate range of power output of

    typical automobiles

  • 167 kW – Tech: power consumption of UNIVAC

    1 computer

  • 250 kW – Tech: highest allowed ERP

    for an FM

    band radio

    station in the United


  • 250 kW to 800 kW – Tech: approximate range of power output of ‘Supercars


(106 watt)

The productive capacity of electrical generators operated by utility

companies is often measured in MW. Few things can sustain the transfer or

consumption of energy on this scale; some of these events or entities include:

lightning strikes, naval craft (such as aircraft

carriers and submarines),

engineering hardware, and some scientific research equipment (such as the supercollider

and large lasers).

For reference, about 10,000 100-watt lightbulbs or 5,000 computer systems

would be needed to draw 1 megawatt. Also, 1 MW equals approximately 1341 horsepower.

Modern high-powered diesel-electric

railroad locomotives

typically have a peak power output of 3–5 MW, whereas a typical modern nuclear

power plant produces on the order of 500–2000 MW peak output.

Gigawatt (109 watt)

Terawatt (1012 watt)

  • 1.7 TW – Geo: average electrical power consumption of the world in 2001
  • 3.327 TW – Geo: average total (gas, electricity, etc) power

    consumption of the U.S.

    in 2001

  • 13.5 TW – Geo: average total power consumption of the human world

    in 2001

  • 44 TW – Geo: average total heat flux from earth’s interior (See

    figure in http://physicsweb.org/articles/news/9/7/16/1)

  • 75 TW – Eco: based on global net

    primary production (= biomass

    production) via photosynthesis

  • 50 to 200 TW – Weather: rate of heat energy release by a hurricane
  • In "Star Trek: The Next Generation", the warp core of the

    fictitious Enterprise-D was able to produce a maximum power output into the

    Terawatt range.

Petawatt (1015 watt)

Exawatt (1018 watt)

  • 1 EW – Astro: Approximate power generated between the surfaces of

    Jupiter and its moon Io due to Jupiter’s tremendous magnetic field.

Zettawatt (1021 watt)

Yottawatt (1024 watt)

  • 5.3 YW – Tech: Power produced by the Tsar

    Bomba fusion bomb, the most powerful device ever made

  • 386 YW – Astro: Luminosity

    of the Sun

Greater than Yottawatt

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December 8, 2006 2:44 pm

And all named after James Watt.
An interesting thing I learned in engineering and math classes in college was that many of our units are named after scientists and engineers. This is especially true in electonics.
Some examples… volts (Volta), amps-ampere (Ampere), farads-charge capacity (Faraday), coloumbs- a unit of charge (Coloumb), just to name a few.
You often run across the same names when learning both higher math and physics, which shows how brilliant many of these guys were.
**** Moderators response:
BTW James Watt invented the steam engine amongst other things.
And a few others names like Roentgens, for radiation.(some bunker humor going on there) Roentgen discovered the X-ray.
On the bunker, are you still “sheltering in place”? Do you need an air-drop of Celebration Ales?

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