The oximeter is a common measuring tool, and the main measuring indexes are pulse rate, blood oxygen saturation, perfusion index and so on. How does the oximeter work? This product is based on advanced optical technology and physiological principle, which provides a convenient, rapid and non-invasive method for medical workers to monitor the oxygenation level of patients. The working principle of oximeter is to reflect the oxygen saturation through the absorption rate of light beams with different wavelengths by peripheral circulating blood. In this issue, Hottech takes you to deeply understand the working condition of oximeter and the application of discrete device products in oximeter.

Working mechanism and composition of oximeter

The working mechanism of mainstream oximeter in the market is five processes, light absorption principle, based on the absorption characteristics of hemoglobin to different wavelengths of light. Hemoglobin absorbs infrared and red light in different degrees under oxygen and anaerobic conditions. Infrared and red light are alternately irradiated, and the sensor of oximeter measures the pulse waveform through the skin. These two kinds of light pass through the skin tissue and are absorbed and reflected by the blood. Red light is mainly absorbed by oxygenated hemoglobin, while infrared light is more sensitive to deoxyhemoglobin. Then the oxygen saturation is calculated, and the oximeter calculates the oxygen saturation according to the absorption degree of red light and infrared light. Pulse waveform analysis, in addition to oxygen saturation, pulse oximeter also provides additional information by analyzing pulse waveform. The shape and amplitude of pulse waveform can reflect the state of cardiovascular system, such as the contraction and relaxation of the heart. Real-time monitoring and alarm, pulse oximeter can monitor the oxygen saturation of patients in real time and give an alarm when abnormal is detected. This enables medical staff to take prompt measures to ensure that patients receive timely support in oxygen supply.

The test data of some oximeters in the market are inaccurate, and the test is delayed. This is because of their different materials, and the performance of chips and components used in oximeters is different, which leads to great changes in the final processed data and a gap in cost.

The oximeter usually includes a microprocessor, a memory, a digital-to-analog converter for controlling the LED, a device for filtering and amplifying the signal received by the photodiode, and an analog-to-digital converter for digitizing the received signal and providing it to the microprocessor.

Take the oximeter produced by a customer as an example, it mainly consists of five components, namely, power supply system, display screen, transmitting system, receiving system and core control system. The power supply system supplies power, with two power supply lines, and the power supply is two batteries. The reading display screen shows oxygen saturation, heart rate, etc. The emitter is to emit signals, and the LED is emitted by this infrared and red light. Among them, the four MOS tubes that drive this LED are SI2300, with voltage of 20V and current of 4A and encapsulated by SOT-23. The specific function of the receiver is to realize the acquisition and conversion of optical signals, and then output them to the core control processing chip through the circuit to calculate the bleeding oxygen saturation or heart rate, and finally display the calculated oxygen saturation or heart rate on the screen.

Application of discrete device products in oximeter

As a conventional electronic product, the functions of discrete devices in oximeter include switching, amplification, rectification, voltage stabilization, etc., and have applications in operational amplification circuits, rectification filter circuits and switching circuits. The products used by Hottech on the circuit board of the whole oximeter include Schottky diode SS14W, switching diode 1N4148, triode S8050 and MOS tube SI2300. The above products are manufactured by Hottech, and you are welcome to consult.

As a professional manufacturer of discrete devices with more than 30 years' experience, Hottech's discrete device products have stable, reliable and safe performance, and the company's product quality and service ability are strong. It has been deeply cultivated in the oximeter industry for many years and has strong strength, and is a quality partner of customers.