A plug valve for a gas stove, consisting at least of a natural-gas nozzle, a propane-gas nozzle, a valve body, a cock, an adjusting rod, an O-shaped ring, a stop ring, a spring, a stop plate, a cover, a pair of screws, and a valve rod. The engine has a chamber deactivation operating mode in which at least one combustion chamber is active and receives fuel and air which are combusted therein and at least one other combustion chamber is deactivated and is supplied with no fuel by the fuel system. The computed relative altitude is displayed adjacent to each range ring displayed. The second electrode is adjacent the piezoelectric layer and the second electrode has an outer perimeter. It is also possible to provide an event request of a manual-feed timing to an application. The image processor also includes an image-signal forming unit which forms image signals representing a composite image of the stored first and second image data for display on a television monitor and a liquid crystal display panel.