Capacitance manometer with digital output
First Claim
Patent Images
1. A capacitance manometer comprising:
- a vacuum or pressure transducer for converting relative changes in vacuum or pressure values into relative changes in transducer capacitance; and
means responsive to the electrical voltage across said transducer capacitance for producing a first signal when said voltage equals a first value;
means responsive to the electrical voltage across said transducer capacitance for producing a second signal when said voltage equals a second value;
means responsive to said first signal for electrically charging said transducer capacitance and responsive to said second signal for electrically discharging said transducer capacitance; and
means responsive to said first and second signals for producing an output frequency signal proportionally related to the value of said transducer capacitance.
1 Assignment
0 Petitions
Accused Products
Abstract
A capacitive pressure or vacuum gauge is disclosed that utilizes a transducer in which a change in capacitance between a movable conductive diaphragm and the wall of the transducer is used to sense changes in pressure or vacuum. The change in capacity is converted directly into a change in frequency of a digital signal by means of a simple resistance/capacitance oscillator in which the capacitive transducer is used as the capacitance.
15 Citations
7 Claims
-
1. A capacitance manometer comprising:
-
a vacuum or pressure transducer for converting relative changes in vacuum or pressure values into relative changes in transducer capacitance; and means responsive to the electrical voltage across said transducer capacitance for producing a first signal when said voltage equals a first value; means responsive to the electrical voltage across said transducer capacitance for producing a second signal when said voltage equals a second value; means responsive to said first signal for electrically charging said transducer capacitance and responsive to said second signal for electrically discharging said transducer capacitance; and means responsive to said first and second signals for producing an output frequency signal proportionally related to the value of said transducer capacitance. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. In a capacitance manometer having a vacuum or pressure transducer including a housing and a diaphragm attached to said housing said diaphragm moving in response to changes in vacuum or pressure applied thereto to form a variable transducer capacitance between said housing and said diaphragm, the improvement comprising:
resistance/capacitance oscillator means responsive to said changes in the transducer capacitance for producing an output signal, said resistance/capacitance oscillator means comprising; means responsive to the electrical voltage across said transducer capacitance for producing a first signal when said voltage equal a first value and for producing a second signal when said voltage equals a second value; and means responsive to said first signal for electrically charging said transducer capacitance and responsive to said second signal for electrically discharging said transducer capacitance so that said resistance/capacitance oscillator produces an output signal whose frequency varies directly and proportionately with changes in the value of said capacitance.
Specification