Shown here are basic sensing resistor bridges. The strain gauges consist either of conductor tracks folded back and forth on itself or single semiconductor tracks bonded to the sample surface. The most common configuration used for pressure sensors is a Wheatstone bridge. These two pictures are about the metal foil and on the metal foil. This type of resistor, on the metal foil, usually changes its resistance when it is either stretching or compressing. When it stretches, the resistance increases, and when compressed, the resistance decreases. So, change in pressure will cause a change in resistance in the bridge resulting in a corresponding output.