Patent ID: 8300383

Claim:
A variable capacitor comprising: a substrate having a top surface; an electrode pattern formed on said top surface of said substrate; at least one conductive contact formed on said top surface of said substrate and spaced apart from said electrode pattern; a dielectric sheet disposed on said top surface of said substrate and covering said electrode pattern; a resilient conductive supporting seat mounted on said dielectric sheet, said conductive supporting seat having a central portion spaced apart from said dielectric sheet, and a contact portion corresponding to said electrode pattern, said contact portion extending downward from said central portion toward said electrode pattern and abutting against said dielectric sheet; an insulating operating cap supported by said conductive supporting seat and disposed over said central portion of said conductive supporting seat; a conductive cover body mounted on said substrate, and covering and electrically contacting said conductive supporting seat, said cover body being connected electrically to said conductive contact, and permitting said operating cap to extend outward; and a biasing member disposed between said conductive supporting seat and said dielectric sheet for biasing said central portion to move away from said substrate; wherein, when said operating cap is depressed, said operating cap forces said contact portion of said conductive supporting seat to deform such that a surface area of said deformed contact portion that contacts said dielectric sheet is increased, thereby changing the capacitance between said conductive supporting seat and said electrode pattern.