The simple medical tools of an OPD visit | Explained

You’ve developed a minor cold. It’s also important that the material that fills the bulb — mercury in this case — has a linear dependence on temperature changes: that is, if it expands by 1 unit for every 1º C change in temperature, it should do so by 10 units for a 10º C change or by 0.1 units for every 0.1º C change. Another common type of thermometer is the thermistor: a semiconductor whose resistance is highly sensitive to changes in temperature; thermistor-based thermometers are today a common sight in clinics and hospitals. An electronic weighing scale works the same way except for the part where the spring’s compression or stretching is converted to a weight measure. The doctor or nurse keeps track of the cuff pressure by its link to the manometer, which measures pressure as the level of mercury in a capillary.