Patent ID: 7901553

Claim:
A system for sensing hydrogen in a gas stream, the system comprising: (a) a thermally conductive, electrically insulative substrate; (b) a metal-gated metal-oxide semiconductor (MOS) gas-sensing element mounted on said substrate, said MOS gas-sensing element comprising a MOS gas sensing capacitor having a capacitance at a bias voltage, said MOS gas-sensing element capable of sensing said hydrogen in said gas stream; (c) a metal-gated metal-oxide semiconductor (MOS) reference element mounted on said substrate, said MOS reference element comprising a MOS reference capacitor having a capacitance, said metal-gate comprising a metal that is inert with respect to said hydrogen in said gas stream, said MOS reference element and said MOS gas-sensing element having congruent electrical properties; and (d) an electronic circuit interconnecting said MOS gas-sensing element and said MOS reference element, said circuit capable of actuating both of said elements, adjusting the bias voltage of said MOS gas-sensing capacitor to match the capacitance of said MOS gas-sensing capacitor with the capacitance of said MOS reference capacitor and driving said MOS reference capacitor and said MOS gas-sensing capacitor with complimentary AC waveforms signals that cancel when added together and having a control loop which drives the bias voltage of said MOS gas-sensing capacitor to maintain a minimum amplitude for a sum of outputs; whereby a concentration of hydrogen in said gas stream has a proportional relationship to a change in the bias voltage.