Learn in the textbookDetection Devices (Distance and Environmental-Quantity Sensors)
DefinitionA pressure sensor (圧力センサー) detects the pressure of a gas or liquid, or a force applied to a surface, and turns it into an electrical signal.
ExplanationOne method, for instance, reads the strain of a thin membrane (a diaphragm) that flexes slightly under pressure as a change in electrical resistance or capacitance. It is used to monitor tire pressure, in smartphone barometers that estimate altitude from changes in air pressure, and in blood pressure monitors.
AnalogyPress a balloon with your finger and you feel how taut it is; this device tells you that tautness as a number.
Memory hookA bag of chips puffs up on a mountaintop because the air pressure outside drops. Altitude and air pressure go hand in hand, so pressure tells you height.