The ornamental design for a highvoltagevariablecapacitor, as shown and described.
FIG. 1 is a top perspective view of a high voltage variable capacitor showing my new design in a typical usage configuration including unclaimed environment;
FIG. 2 is a front side view thereof in another usage configuration including unclaimed environment;
FIG. 3 is an underside view thereof without unclaimed environment;
FIG. 4 is a front end view thereof;
FIG. 5 is a top elevation view thereof; and,
FIG. 6 is a rear end view thereof.
The broken line portion of the figure drawings is included to show unclaimed subject matter only and forms no part of the claimed design.