Described are techniques for selecting options used with current sensor data characterizing vibration caused by rotating blades. The switch circuit may include one or more arrangements of transistors coupled in a cascode configuration. A buckling plate is extended from one lateral side of the bulb seat; the buckling plate has a concave portion which is bendable; a distal end of the buckling plate has a guide inclined surface and a hook; one lateral side of the base has a buckle for receiving the buckling plate. However, as the machine workload rises, demands on the engine may become greater, and at a predetermined threshold of engine workload the engine idle speed may be automatically increased to a higher set point. The battery pack detects consumption current when a load is not turned on, and shuts off power when a load is turned off or in stand-by mode, thereby preventing consumption current of the load from flowing.