1. Transducer Shubham Dholakia - Feb2014 Roll no - 7

2. Transducer Contents : 1. Introduction 2.Need 3. Classification 4.Active and Passive transducers 5. Analog and Digital transducers 6. LVDT Construction, working and applications. 7. Applications of Transducers Shubham Dholakia - Feb2014 Roll no - 7 3. Transducer A transducer is a device which converts one form of energy into another. Energy types include thermal, chemical, acoustic, mechanical, Electromagnetic electrical. Shubham Dholakia - Feb2014 Roll no - 7 4. need of Transducers Usually the input to an instrumentation system is a non-electrical quantity. In order to convert a non electrical quantity into an electrical quantity a transducer is required. Advantage : wear and tear is absent, the quantity can be amplified, recorded as well as indicated. Input : Non- electrical T R A N S D U C E R Output : Electrical Shubham Dholakia - Feb2014 5. Classification of Transducers Shubham Dholakia - Feb2014 6. Active and passive transducers Active Transducers : The transducers which do notdo not require an external power supplyrequire an external power supply for their operation are called as active transducers. Eg. Piezoelectric transducers. Passive Transducers : The transducers which require an external power supplyexternal power supply for their operation are called as passive transducers. Eg. LVDT. Shubham Dholakia - Feb2014 7. Analog and Digital Transducers Analog transducers: They convert the input physical phenomenon into an analog output that is a continuous function of time. E.g. LVDT. Digital Transducers: They convert the input physical phenomenon in discrete steps of electrical output i.e. in the form of pulses. E.g. Rotary encoders. Shubham Dholakia - Feb2014 8. LVDT Linear Voltage Differential TransformerLVDT is a device which converts the displacementdisplacement of core into an electrical outputelectrical output. As seen in fig(a) LVDT consists of 2 secondary windings2 secondary windings coil 1 and coil 2. It consists of one primaryone primary windingwinding to which a constant ac voltage is applied. It also consists of a soft iron core with an arm attached to it. Shubham Dholakia - Feb2014 9. LVDT - Working When no displacementno displacement is attached to the core, the position of the core remains unchanged and the flux linking with both the coils are equal. Thus, Vo = 0.Thus, Vo = 0. When positive displacementpositive displacement is attached to the core the the core moves towards the left side of the core and we get Vo = V2 V1Vo = V2 V1 since flux linking with secondary winding s2 is greater than flux linking with winding s1. Shubham Dholakia - Feb2014 10. LVDT Working When negative displacementnegative displacement is attached/applied to the core the core moves more towards right side of the core and we get Vo = V1 V2 since flux linking with s1 is greater than s2. Shubham Dholakia - Feb2014 11. LVDT - Applications Used to measure linear displacement Useful for measurement of tension in cord. It is used to measure weight or pressure exerted by liquid in the tank. Shubham Dholakia - Feb2014 12. Applications of a Transducer Loudspeaker, earphone: converts electrical signals into sound. Antenna: converts propogating electromagnetic waves to and from conducted electrical signals. Hall effect sensor: It converts magnetic field level into an electrical signal. Electro galvanic fuel cell. Shubham Dholakia - Feb2014 13. THANK YOU Shubham Dholakia - Feb2014