Biotelemetry consists of two parts i.e. Bio and Telemetry. Bio is related to living being or process or phenomenon occurring in the human body. Telemetry is the measurement at a distance. So, Biotelemetry is a method of measuring biological parameters from a distance. The transmission of data from the point of generation to the point of … Read more
The measurement of a given quantity is essentially an act or result of comparison between a quantity, whose magnitude (amount) is unknown with a similar quantity whose magnitude (amount) is known, the latter being called standard. Measurement involves the use of the instrument as a physical means of determining quantities or variables. The instruments serve … Read more
Static Sensitivity Static Sensitivity of an instrument or an instrumentation system is defined as the ratio of the magnitude of the output signal or response to the magnitude of an input signal or the quantity being measured. The reciprocal of sensitivity is defined as inverse sensitivity or deflection factor. The sensitivity of an instrument should … Read more
Blood Flowmeters Blood flow-meters are the devices that monitor the blood flow in various blood vessels and measure the cardiac output. In the blood vessels, the blood flow rate is maximum along the axis of the vessel and decreases with the square of the distance from the axis, reaching zero at the wall … Read more
Fig: LVDT cross-section (source: te.com ) Linear Variable Differential Transformer (LVDT) is an inductive transducer that we discussed in the previous article. It is basically used to translate linear motion into electrical signals. LVDT Construction LVDT consists of one primary winding and two secondary windings. All these windings are wound on a cylindrical former. … Read more
Fig. Resistive Potentiometers (POT) (source: instructables.com) Potentiometer A potentiometer consists of a resistive element having a sliding contact. This sliding contact is known as a wiper. A potentiometer is also called as POT because it is used in voltage division. It is a resistive and passive transducer. Depending upon the motion of wiper, potentiometer are … Read more
Fig. Strain Gauges (source: omega.com) Strain gauge A strain gauge is an electrical transducer which is used for measuring mechanical surface strain. Basic Principle of Strain Gauge When stress is applied to the metal conductor, its resistance changes owing to change in length and cross-sectional area of the conductor. The resistance of the conductor under … Read more
Fig. Thermocouple (source: sterlingsensors.co.uk) What is a Thermocouple? A thermocouple consists of a pair of dissimilar wires joined at one end. It is an active transducer. On the other hand, RTD and thermistors are passive transducers. Thermocouple work on the principle of Seebeck effect. According to Seebeck effect, if two dissimilar metals are joined together … Read more
Piezoelectric Transducer A piezoelectric transducer is one that can generate a voltage proportional to the stress applied to it. These transducers work according to the piezoelectric effect. When a mechanical force or pressure is applied across the piezoelectric crystal, an electric potential appears across the surfaces of crystal. This generation of electric potential is due … Read more
Hall Effect Transducers Hall Effect Transducers are the transducers which work on the principle of hall effect. According to hall effect, if a conducting material strip carries current in the presence of a transverse magnetic field; an EMF is produced between two edges of the conductor in a direction perpendicular to both the magnetic field … Read more