Patent ID: 8893563

Claim:
A differential capacitance torque sensor, comprising: a housing; upper and lower fixed substrates being spaced apart and oriented parallel with respect to one another, said upper and lower fixed substrates being secured in said housing; first and second longitudinally opposed upper electrodes respectively secured to first and second longitudinally opposed ends of said upper fixed substrate; first and second longitudinally opposed lower electrodes respectively secured to first and second longitudinally opposed ends of said lower fixed substrate; a longitudinally-extending, conductive proof mass centrally positioned between said upper and lower fixed substrates, said longitudinally-extending, conductive proof mass being pivotal about a central axis thereof, wherein a first end of said longitudinally-extending, conductive proof mass is positioned between said first upper electrode and said first lower electrode defining a first upper capacitor having a first upper capacitance C 1 and a first lower capacitor having a first lower capacitance C 2 , a second end of said longitudinally-extending, conductive proof mass being positioned between said second upper electrode and said second lower electrode defining a second upper capacitor having a second upper capacitance C 3 and a second lower capacitor having a second lower capacitance C 4 ; a first voltage source having a constant voltage V 1 electrically connected across said longitudinally-extending, conductive proof mass, said first upper capacitor and said second lower capacitor; and a second voltage source having a constant voltage V 2 connected in series with said first voltage source, said second upper capacitor and said first lower capacitor, wherein the voltage V 2 is given by V 2 = γ γ + 1 ⁢ V 1 , wherein γ is a parameter defined as γ = C 2 + C 3 C 2 + C 4 - 1.