Towards an Electronic Kilogram Physics 250 Victor Acosta NOTE: Almost everything in this report was taken from NIST websites.

The Old Standard: "Le Gran K" Held In Sevres, France Only 1/7 SI units using physical artifact Δm/m = 30 ppb

Ideas for New Standard X-Rays in Si –Avogadro’s #, N A 340 ppb (2003) Watt-balance: EM vs. G –Planck Constant, h 52 ppb (2005) Link to "invariant" quantum phenomena

The Watt Balance Balance Gravity Force with EMF Find value for h, Planck’s Constant

Physics

Animation (if it works)

Measurements: Voltage Hg Battery Stabilized I-Source Zener Diode Josephson Array Voltage Determine f with GPS Atomic clock

Measurements: Velocity 3 HeNe Laser systems give v and z Easily referenced to Meter standard: λ HeNe = nm

Measurement: Current Use DVM (Josephson ref.) to measure V across R Get R via Quantum Hall Effect DVM

Measurement: Gravity Easy to reference gravity! Use nearby gravimeter < 10 meters away Reference with HeNe, GPS When scale is balanced

Watt-Balance UC Basic references (error mode)nW/W Mass (force)15 Voltage, square error (current, voltage)2 Resistance (current)10 Time, linear error (voltage, current, velocity)0.5 Length (velocity)3 Local gravity acceleration (force)30 TOTAL RMS52