Definition of transducers –
A transducer is a device which converts one quantity into another quantity. examples are microphone, incandescent light and electric motor. A microphone converts sound into electric impulses. A incandescent light bulb converts electrical energy into light. An electric motor converts electrical energy into motion. Some actuators are transducers, an actuator is a device that actuates or moves something or creates motion such as gear, hydraulic cylinder. The light bulb, motor, microphone are the both actuator and transducers. the motor compress electrical energy into motion, the output portion of the motor is used to drive levelers, gears and piston up and down.
2)signal conditioning or processing device
3) output device
Any measurement system consists of these three components, input device is going to receive the measuring signal and measuring instrument receives the input signal, it does the functions like ampily or attenuate or filter the input signal and then expectable output format given by the output device it is the function of these three components of a measurement system.
Transducer is a device which convert the non-electrical quantity into electrical quantity, so that electrical quantity can be used for other instrumentation and measurement systems.
Need for the transducer –
If we have non electrical quantity, then if we want do some electrical processing over it, like for measurement, manipulation and for the control systems we have to apply electrical methods, we have to convert non electrical quantity into electrical quantity and that’s why there is a need for the development of the transducers.
Transducer is a device which converts one form of energy into another form like mechanical energy can be converted into electrical energy and electrical can be converted into optical energy, so in this way one form of energy is converted into another form by the transducers.
Example: Mercury thermometer
Suppose if we want to measure a variation of the temperature, if we measure the room temperature by using mercury thermometer. It is a device used to measure the variations in the temperature by measuring the variations in the length of the mercury column.
According to variations in the temperature the mercury in column is raise by its level, so by measuring the level of mercury we measuring the variations in temperature otherwise it will be not possible for us to measure the variation of temperature in room.
Manometer is used for measuring the pressure, so here we directly measuring the pressure variations in a system. The manometer is going to directly give the reading over the calibrated scale. The temperature variations, pressure variations all these are non-electrical quantities and these non-electrical quantity of one form of energy is converted into another form by the transducer. The mercury thermometer and manometer are the type of transducers, which converts one form of energy into another form. now there are many physical parameters like heat, intensity of light, flow rate, liquid level, humidity, PH, there are no direct methods for measuring these quantities, so we are going to use the transducers which convert these physical quantities into electrical quantities and then we can easily measure the value of these parameters.
Transducers provide an output signal when stimulated by a mechanical or a non-mechanical input. It is not necessary that always the physical quantity or non-electrical quantity or mechanical quantity. It can be pressure, force, light etc., any non-mechanical or mechanical input it can be converted into electrical output. As the output given by the transducer is an electrical output or some form of an energy. There is a division of transducers on the basis of major output, if the output is electrical quantity it will be an electrical transducer, then output is mechanical quantity it will be mechanical transducers, so depending upon the nature of the output given by the transducer they are divided into different categories. Most probably we are use the electrical transducers they are widely used and they are having applications in many fields, because most of the instrumentation and measurement systems they require the electrical method.
Transducer basically consists of two elements, sensing element and transduction element. sensing element is going to sense the input signal and transduction element is going to do the conversion of non-electrical into electrical.
In thermocouple we are having two metals which are connected with each other and at the junction doing the temperature changes at one time kept the temperature of 0°c and after kept temperature T°c. Due to this temperature difference the heat which is generated that is converted into voltage. here non-electrical quantity heat is converted into electrical quantity of voltage, this thermocouple is acting as a sensing element and transduction element also, it is sensing the changes in the input signal and generating the electrical signal.
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