Our daily activities are getting automated every day. Control System plays an important role in making our life automated and modernized. A microwave, refrigerator, an air conditioner, a geezer, an automatic iron, are some examples of a control system. Many engineering fields use control system principle in many applications. System It is an interconnection … Read more
When the current flows to the conductor, a magnetic field is produced around it. The nature of magnetic field around a straight current carrying conductor is like concentric circles. The center of these concentric circle is axis of the current carrying conductor. The direction of these circular magnetic lines is dependent upon the direction of flow … Read more
Resistance Temperature Detector (RTD) It is a device which senses the resistance change on account of temperature change. This property is used for measurement of temperature. Resistance Temperature Detector (RTD) is also called as a resistance thermometer. It uses the change in electrical resistance to measure the temperature. Construction of RTD RTD elements consist of … Read more
In 1831, Micheal Faraday formulated two important laws on the basis of certain experiments that shows a relationship between the electric circuit and magnetic field. These laws are called Faraday’s laws of electromagnetic induction. Faraday’s First Law According to Faraday’s First Law, Whenever a conductor is placed in a varying magnetic field, an EMF is … Read more
Fig. NTC Thermistors (source: ussensor.com) Thermistors These are the thermally sensitive resistors. The resistance of a thermistor varies as a function of temperature. The thermistor is also called thermal resistors. It is a resistive temperature transducer. Thermistors are composed of semiconductor materials. It is composed of a sintered mixture of metallic oxides such as Mn, … 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