4.1 Introduction We hope to acquire measurands with no errors If the characteristic curve is a straight line the transducer is known as a linear transducer But in most cases the characteristic of a transducer is not a linear one and the transducer is called a nonlinear transducer
• We hope to acquire measurands with no errors. • If the characteristic curve is a straight line, the transducer is known as a linear transducer. • But in most cases, the characteristic of a transducer is not a linear one, and the transducer is called a nonlinear transducer. 4.1 Introduction
4.2 Classifications of transducers Different ways are employed for the classification of transducers One way is to classify transducers in terms of measured quantities Force transducers Ⅴ elocity transducers Temperature transducers
• Different ways are employed for the classification of transducers – One way is to classify transducers in terms of measured quantities: • Force transducers • Velocity transducers • Temperature transducers 4.2 Classifications of transducers
4.2 Classifications of transducers Another way is to make the classification in terms of the operating principles of transducers or the signal converting principles in transduction Structure-type transducers: transduce signals by its structural variations Capacitive transducer: changes capacitance by varying gaps between two electrode plates or the common area of the two plates Sliding-contact resistive transducer: changes resistance by changing the length of wire by moving the slide
– Another way is to make the classification in terms of the operating principles of transducers or the signal converting principles in transduction • Structure-type transducers : transduce signals by its structural variations ▪ Capacitive transducer : changes capacitance by varying gaps between two electrode plates or the common area of the two plates ▪ Sliding-contact resistive transducer : changes resistance by changing the length of wire by moving the slide 4.2 Classifications of transducers
4.2 Classifications of transducers Physical-property-type transducers based on the change in physical properties of its sensing element material to realize signal conversion Pressure accelerometer: based on the piezoelectric effect of its quartz crystal material a Photo-sensitive resistor: changing its resistance when exposed to light
• Physical-property-type transducers : based on the change in physical properties of its sensing element material to realize signal conversion ▪ Pressure accelerometer : based on the piezoelectric effect of its quartz crystal material ▪ Photo-sensitive resistor : changing its resistance when exposed to light 4.2 Classifications of transducers
2 Classifications of transducers a transducer is also an energy converting element which converts one form of the measured energy into another form of energy to a predefined accuracy or into the same energy form of other values We also divide transducers into energy-converting and energy-controlling transducers An energy-converting transducer( passive transducer) operates with the energy from the measurand An energy-controlling transducer(active transducer)is powered by external energy source, the energy variations being controlled by the measurand
• A transducer is also an energy converting element, which converts one form of the measured energy into another form of energy to a predefined accuracy or into the same energy form of other values. • We also divide transducers into energy-converting and energy-controlling transducers. • An energy-converting transducer ( passive transducer) operates with the energy from the measurand. • An energy-controlling transducer (active transducer) is powered by external energy source, the energy variations being controlled by the measurand. 4.2 Classifications of transducers