Tag: Biomedical Instrumentation
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Fleisch Pneumotachometer Operation & Biomedical Application
Fleisch Pneumotachometer is one of the most common types of airflow transducers. It consists of a straight short-tube with a fixed screen obstruction in the middle that produces a slight pressure drop as the air is passed through the tube. The pressure drop created across the screen is measured by a differential pressure transducer. The…
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Key Features of EMG Amplifiers
The amplifiers used for clinical EMG recording must meet same strict specifications for low-leakage currents as do ECG, EEG, and any other amplifiers used to measure human body potentials. EMG amplifier gains are typically x1000 and their bandwidths reflect the transient nature of the single motor unit (SMU) action potentials. An EMG amplifier is generally…
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5 Established Isolation Architectures for Medical Isolation Amplifiers
Medical isolation amplifiers provide an ultra-low conductive pathway between the input (patient) terminals and the output terminals and ground. This pathway provides what is called ohmic or galvanic isolation for a patient. In medical applications, this isolation is required for reasons of patient safety. The dc resistance between input and output terminals is typically on…
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Biosignals Data Acquisition
Biological signals are often very minute and typically contain unwanted interference or noise. Such interference has the detrimental effect of obscuring relevant information that may be available in the measured signal. Noise can be extraneous in nature arising from sources outside the body, such as thermal noise in sensors or 60-cycle noise in the electronic…
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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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Types of EMG Electrodes Commonly Used in Medical Measurements
We have different types of biopotential electrodes that are used in recording electromyographic (EMG) signals from different muscles in the body. The shape and size of the recorded EMG signals depend on the electrical property of these electrodes and the recording location. For non-invasive recordings, proper skin preparation, which normally involves cleansing the skin with…
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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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ECG Electrodes
A typical flexible ECG electrode is composed of certain types of polymers or elastomers that are made electrically conductive by the addition of fine carbon or metal powder. These electrodes are available with pre-pasted AgCl gel for quick and easy application on the skin using double-sided peel off adhesive type. Related: Electrocardiogram (ECG) The common…
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Radionuclide Imaging Techniques
The radionuclide imaging devices place radionuclides, called tracers, within the body. We have 3 types of imaging that include the following: Let’s discuss briefly each of the above listed imaging techniques: Single Photon Emission Computed Tomography (SPECT) SPECT uses a radionuclide with relatively longer half-life. (The half-life is the time, it takes half the radionuclides…
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Key Considerations for Biopotential Measurements
Biopotential measurements are done using different types of specialized electrodes. The work of these recording electrodes is to couple the ionic potentials generated inside the body to an electronic instrument. Biopotential electrodes are classified either as non-invasive (skin surface) or invasive (for example microelectrodes or wire electrodes). Related: Types of Electrodes used in Medical…