Variable capacitor
View Patent ↗A variable capacitor comprising: a first elongate member comprising a first electrically conductive portion positioned towards a first distal end of the first elongate member and a second electrically conductive portion positioned towards a second distal end of the first elongate member, wherein the first elongate member is configured to pivot on a first fulcrum positioned between the first and second electrically conductive portions, wherein a first distance between the first fulcrum and the first electrically conductive portion of the first elongate member is different to a second distance between the first fulcrum and the second electrically conductive portion of the first elongate member; a second elongate member comprising a first electrically conductive portion positioned towards a first distal end of the second elongate member and a second electrically conductive portion positioned towards a second distal end of the second elongate member, wherein: one of the first and second elongate members is a cathode and the other of the first and second elongate members is an anode, a first capacitor is formed by the respective first electrically conductive portions of the cathode and anode, wherein a capacitance of the first capacitor is a function of a first pivoting angle of the first elongate member on the first fulcrum, and a second capacitor is formed by the respective second electrically conductive portions of the cathode and anode, wherein a capacitance of the second capacitor is a function of the first pivoting angle of the first elongate member on the first fulcrum, the first and second electrically conductive portions of the cathode are connected to a positive voltage of a first electric circuit, the first and second electrically conductive portions of the anode are connected to a negative voltage of the first electric circuit, such that the first and second capacitors are connected in parallel, and wherein: application of an electrical potential difference by the first electric circuit causes pivoting of the first elongate member and a corresponding variation in the capacitance of the first capacitor that is proportional to the electrical potential difference and a corresponding variation in a capacitance of the second capacitor that is inversely proportional to the electrical potential difference, wherein the magnitude of the variations in capacitances of the first and second capacitors are different such that a sum of the capacitances of the first and second capacitor varies as a function of the electrical potential difference.
1 . A variable capacitor comprising:
a first elongate member comprising a first electrically conductive portion positioned towards a first distal end of the first elongate member and a second electrically conductive portion positioned towards a second distal end of the first elongate member, wherein the first elongate member is configured to pivot on a first fulcrum positioned between the first and second electrically conductive portions, wherein a first distance between the first fulcrum and the first electrically conductive portion of the first elongate member is different to a second distance between the first fulcrum and the second electrically conductive portion of the first elongate member;
a second elongate member comprising a first electrically conductive portion positioned towards a first distal end of the second elongate member and a second electrically conductive portion positioned towards a second distal end of the second elongate member,
wherein:
one of the first and second elongate members is a cathode and the other of the first and second elongate members is an anode,
a first capacitor is formed by the respective first electrically conductive portions of the cathode and anode, wherein a capacitance of the first capacitor is a function of a first pivoting angle of the first elongate member on the first fulcrum, and a second capacitor is formed by the respective second electrically conductive portions of the cathode and anode, wherein a capacitance of the second capacitor is a function of the first pivoting angle of the first elongate member on the first fulcrum,
the first and second electrically conductive portions of the cathode are connected to a positive voltage of a first electric circuit,
the first and second electrically conductive portions of the anode are connected to a negative voltage of the first electric circuit, such that the first and second capacitors are connected in parallel, and wherein:
application of an electrical potential difference by the first electric circuit causes pivoting of the first elongate member and a corresponding variation in the capacitance of the first capacitor that is proportional to the electrical potential difference and a corresponding variation in a capacitance of the second capacitor that is inversely proportional to the electrical potential difference, wherein the magnitude of the variations in capacitances of the first and second capacitors are different such that a sum of the capacitances of the first and second capacitor varies as a function of the electrical potential difference.
2 . A variable capacitor as claimed in claim 1 , wherein application of the electrical potential difference by the first electric circuit causes pivoting of the first elongate member due a torque experienced by the first elongate member in a first direction being a product of a force of electrostatic attraction between the first electrically conductive portions of the first capacitor and the first distance between the first fulcrum and the first electrically conductive portion of the first elongate member being greater than a torque experienced by the first elongate member in a second direction being a product of a force of electrostatic attraction between the second electrically conductive portions of the second capacitor and the second distance between the first fulcrum and the second electrically conductive portion of the first elongate member.
3 . A variable capacitor as claimed in claim 2 , wherein the first distance between the first fulcrum and the first electrically conductive portion of the first elongate member is greater than the second distance between the first fulcrum and the second electrically conductive portion of the first elongate member such that the sum of the capacitances of the first and second capacitor is proportional to the electrical potential difference.
4 . A variable capacitor as claimed in claim 2 , wherein the second distance between the first fulcrum and the second electrically conductive portion of the first elongate member is greater than the first distance between the first fulcrum and the first electrically conductive portion of the first elongate member and, prior to application of the electrical potential difference, the first pivoting angle of the first elongate member is such that a first separation distance between the first electrically conductive portions of the first capacitor is less than a second separation distance between the second electrically conductive portions of the second capacitor, such that the sum of the capacitances of the first and second capacitor is inversely proportional to the electrical potential difference.
5 . A variable capacitor as claimed in claim 1 , wherein the second elongate member is configured to pivot on a second fulcrum positioned between the first and second electrically conductive portions of the second elongate member, wherein a first distance between the second fulcrum and the first electrically conductive portion of the second elongate member is different to a second distance between the second fulcrum and the second electrically conductive portion of the second elongate member, wherein a capacitance of the first capacitor is a function of a second pivoting angle of the second elongate member on the second fulcrum and a capacitance of the second capacitor is a function of the second pivoting angle of the second elongate member on the second fulcrum.
6 . A variable capacitor as claimed in claim 5 , wherein application of the electrical potential difference by the first electric circuit causes pivoting of the second elongate member due a torque experienced by the second elongate member in the second direction being a product of a force of electrostatic attraction between the first electrically conductive portions of the first capacitor and the first distance between the second fulcrum and the first electrically conductive portion of the second elongate member being greater than a torque experienced by the second elongate member in the first direction being a product of a force of electrostatic attraction between the second electrically conductive portions of the second capacitor and the second distance between the second fulcrum and the second electrically conductive portion of the second elongate member.
7 . A variable capacitor as claimed in claim 6 , wherein the first distance between the second fulcrum and the first electrically conductive portion of the second elongate member is greater than the second distance between the second fulcrum and the second electrically conductive portion of the second elongate member.
8 . A variable capacitor as claimed in claim 6 , wherein the second distance between the second fulcrum and the second electrically conductive portion of the second elongate member is greater than the first distance between the second fulcrum and the first electrically conductive portion of the second elongate member and, prior to application of the electrical potential difference, a second pivoting angle of the second elongate member is such that the first separation distance between the first electrically conductive portions of the first capacitor is less than the second separation distance between the second electrically conductive portions of the second capacitor.
9 . Apparatus comprising the variable capacitor as claimed in claim 1 .
10 . An additive manufacturing apparatus for manufacturing an article, the apparatus comprising:
a computer system;
a first additive manufacturing component adapted to form non-electrically conductive three dimensional structures;
a second additive manufacturing component adapted to form electrically conductive three dimensional structures;
wherein the first and second additive manufacturing components are operable under control of the computer system, the computer system being adapted to control the components to form a variable capacitor or apparatus as claimed in claim 1 .
11 . A computer system for controlling an additive manufacturing apparatus, the additive manufacturing apparatus being adapted to manufacture three dimensional structures from both non-electrically conductive and electrically conductive materials simultaneously, the computer system being operable to control the additive manufacturing apparatus to form a variable capacitor or apparatus as claimed in claim 1 .