Tag: Biomedical sensors and transducers
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Biomedical Sensor Specifications
The need for accurate medical diagnostic procedures places stringent requirements on the design and use of biomedical sensors. Depending on the intended application, the performance specifications of a biomedical sensor may be evaluated in vitro and in vivo to ensure that the measurement meets the design specifications. The following definitions are typically employed when describing…
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What is a Biosensor?
This is a biological sensor that has the following features: Biosensors are typically miniature and include monitoring of blood gas and biochemical concentrations additionally, physical quantities such as force, shear, potential, etc. Biosensors can be divided into those that measure electrical properties e.g. pH meters, CO2 electrodes, O2 electrodes, field-effect transistor-based biosensors, etc. and those…
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Microelectromechanical System Transducers (MEMS)–Based Medical Sensors
Microelectromechanical system transducers (MEMS) are fabricated using solid-state micromachining techniques that are typically employed by the semiconductor industry in the production of integrated circuits (ICs). Related: The application of Microprocessors in Medical Instrumentation A pressure sensor based on MEMS technology is based on the deflection of a micromachined silicon diaphragm mounted on a piezoelectric transducer…
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The General Principle of Fiber Optic-based Sensor
Optical sensors are typically interfaced with an optical unit. This optical component supplies the excitation light, which may be from a monochromatic source such as a diode laser or from a broadband source e.g. quartz-halogen that is filtered to provide a narrow bandwidth of excitation. Typically, two wavelengths of light are employed: one that is…
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Clinical Applications of NTC Thermistors
Thermistors are certainly the most used transducers for medical temperature measurements. Their properties facilitate clinically difficult measurements that include: hypothermia, transcutaneous measurements during cardiopulmonary bypass, testicular temperature measurements in reproductive medicine, continuous monitoring of preterm infants and personal heat strain monitoring in occupational medicine. Thermistors are also extensively used in a variety of clinical and…
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Blood Glucose Sensors
The accurate measurement of blood glucose is essential in the diagnosis and long term management of diabetes. In this article, we discuss the use of biosensors for the continuous measurement of glucose levels in the blood and other body fluids. Glucose is the main circulating carbohydrate in the body. In normal individuals, the concentration of…
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How Liquid Crystal Sensors are used in Biomedical Measurements
The principle of operation of liquid crystal sensors is based on the fact that liquid crystals change their state in such way that they modify passive scattering or absorption of light. As the crystal melt, the three-dimensional order becomes a two-dimensional or one dimensional order, layers or strands form that can be seen as a…
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Key Features of a Disposable Blood Pressure Sensor
Disposable blood pressure sensors are made of clear plastic so that air bubbles are easily seen Saline flows from an intravenous (IV) bag through the clear IV tubing and the sensor to the patient. This is used to flush out blood out of the tip of the indwelling catheter to prevent clotting. A lever can…
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The Functions of Signal Conditioners in Biomedical Measurement Systems
In a Biomedical measurement system, the electrodes pick up the bioelectrical potential whereas the transducer converts the physiological signal to be measured into a usable electrical output. The outputs from the Bioelectrodes/transducers are then converted into an electrical quantity that is suitable for operating a display or recording device with the help of a signal…
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Types of Transducers used in Biomedical Measurement Applications
What is a transducer? A transducer is a device that converts one form of energy or variable into another form of energy or variable. A transducer is required to convert physiological variables into electrical signals which are easier to be further processed. We have a number of factors which are considered in choice of a…