Abstract: In a capacitive sensor apparatus, a capacitive sensor includes a plurality of physical-quantity-detection capacitors each having a movable electrode and a fixed electrode. A conversion device operates for converting an output signal of the capacitive sensor into an apparatus output signal. Each of the physical-quantity-detection capacitors is selectively connected and disconnected to and from the conversion device. A determination is made as to whether or not each of the physical-quantity-detection capacitors fails in response to the sensor output signal. When it is determined that first one of the physical-quantity-detection capacitors fails, the first one is disconnected from the conversion device and second one of the physical-quantity-detection capacitors is connected to the conversion device.

Abstract: A capacitive physical load sensor includes a substrate, which has fixed electrodes, and a diaphragm, which has movable electrodes. The diaphragm is located across a gap from the substrate, and retaining parts for the diaphragm are formed around the diaphragm. Protruding parts extend into the gap from the diaphragm or from the substrate. The protruding parts support the diaphragm at different levels of deformation to alter the characteristics of the diaphragm and extend its range.

Abstract: An interrogation responder system composed of a transmitter stationarily mounted in a certain fixed place and a receiver mounted on a mobile object. The receiver on the mobile side starts the operation when a power is supplied to the entire circuit in accordance with a wake-up signal from the transmitter on the fixed side so as to modulate the electromagnetic signal emitted from the transmitter on the fixed side in accordance with a predetermined code and reflect a response. This enables continuing bilateral communication of a command, data and so forth. By starting communication between the transmitter and the receiver by a direct wave of a carrier signal in a microwave band after sensing that the receiver on the mobile side has entered a good communication zone, secure communication is enabled at a sufficient electric field strength.