Description:A pulse oximeter measures the saturation of blood oxygen in the bloodstream. Since oxygen saturation can reflect early medical problems such as the heart and lungs, this reading is useful as a general health monitoring indicator.It works on the basis of the light absorption properties of hemoglobin in the blood. Oxygenated hemoglobin absorbs more infrared light than red light, while deoxyhemoglobin absorbs more red light than infrared light. Therefore, the red and infrared leds in the oximeter alternately emit light, and the photodiode receives the light signal that is not absorbed. The ratio of red and infrared light received by the photodiode is used to calculate the percentage of oxygen in the blood. According to the pulsation characteristics of the arterial blood flow, the pulse rate and intensity are also determined during the measurement.