Sensor chips are dies incorporating semiconductor circuit elements that are used to convert changes to some physical parameter to an electrical signal. There are several kinds of sensor chips: temperature, gas and liquid pressure, load cells (force sensors), chemical (pH, oxygen, carbon dioxide), magnetic, mechanical (acceleration, position, pressure, knock, rotation), optical (single-chip cameras, edge detectors, and image pattern recognizers), medical (protein interactions) and others. Like other semiconductors, a sensor chip can be flexible, and can be manufactured as a signal conditioning chip, a stand-alone transducer, or a combination.