Bridge voltage inversion circuit for vacuum gauge and pressure gauge sensor having the voltage inversion circuit

A bridge voltage inversion circuit for a pressure gauge comprising:

• a transformer including a primary winding and a secondary winding that outputs a bridge voltage;
• a first sensor capacitor connected to a first side of the secondary winding of the transformer;
• and
• a second sensor capacitor connected to a second side of the secondary winding of the transformer, wherein the first and second sensor capacitors sense and respond to a pressure, a capacitance of the second sensor capacitor is at a minimum when the pressure is at vacuum, and the first sensor capacitor and the second sensor capacitor are selected so that the capacitance of the second sensor capacitor at vacuum is less than a capacitance of the first sensor capacitor at vacuum, and wherein the bridge voltage is at a maximum amplitude when the pressure is at vacuum and a fold-over pressure at which the bridge voltage is at the minimum amplitude is greater than a full-scale pressure.

A pressure gauge sensor, comprising:

• a transformer including a primary winding and a secondary winding that outputs a bridge voltage;
• a first capacitor with one end at which pressure is applied and another end connected to a first side of the secondary winding of the transformer;
• and
• a second sensor capacitor with one end at which the pressure is applied and another end connected to a second side of the secondary winding of the transformer, wherein the first and second sensor capacitors sense and respond to a pressure, a capacitance of the second sensor capacitor is at a minimum when the pressure is at vacuum, and the first sensor capacitor and the second sensor capacitor are selected so that the capacitance of the second sensor capacitor at vacuum is less than a capacitance of the first sensor capacitor at vacuum, and wherein the bridge voltage is at a maximum amplitude when the pressure is at vacuum and a fold-over pressure at which the bridge voltage is at the minimum amplitude is greater than a full-scale pressure.