 In 1990, a fixed conventional value was defined for use in resistance calibrations worldwide.On 16 November 2018, the 26th meeting of the General Conference on Weights and Measures decided to fix exact values of (the Planck constant) and (the elementary charge), superseding the 1990 value with an exact permanent value .The MOSFET (metal-oxide-semiconductor field-effect transistor), invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959, enabled physicists to study electron behavior in a nearly ideal two-dimensional gas.