LDVT
A LDVT ( Linear variable Differential Transformer) Can be usedfor the conversion of displacement to electrical signal where it is used as secondary transducer and it can beused for measurements of displacement where it is used as primary transducer.
Characteristics
Residual voltages due to harmonics in supply voltage and due to external magnetic filed or stray capacitance
Sensitivity of LDVT
= Output Voltage / Input Voltage
Capacitive Transducer
Principle Charge of capacitance with
* charge of overlapping area
* charge of distance between plates
* charge of dielectric medium between the plates
THERMISTORS
Thermistor are temp. Sensitive with negative temp. Cofficient
Resistance temp. Characteristics of Thermistor is
- RT1 = RT2 exp { b Bita [1/T1 - 1/T2]}
Where , RT1 = Resistance of Thermistor at absolute temp. T1K
RT2 = resistance of Thermistor at absolute Temp. T2K
Bita = a constant depending upon the material of thermistor or temp. Cofficient in Kelvin.
RTD ( Resistance Thermo Detector )
Principle the change of resistance of a conductor with change in temperature . RTD had positive temperature coefficient and each compressed various matals as platinum , copper , nickel and nickel alloy .
Also check - Electromechanical Energy Conversion | Electrical Machine
Thermocouple
Principal seebeck effect
emf is when there is a temperature difference between two junction of the two metals .
Emf induced
- E = a( delta ∅ ) + b ( delta ∅ )²
Where a , b = Constant
Delta thita = difference in temperature between the hot thermocouple junction and the reference junction of thermocouple degree Celsius
Note - thermocouple are active transducer
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