Classification of Transducers

1. Based on the Physical phenomenon

1. Primary: The transducer which sends the measurement and converts them into another variables[ displacement, strain, etc.] and whose output forms the input of transducer is called as Primary transducer.

1. Bourdon Tube: Used in Pressure measurements.

2. Strain Gauge: Used in force and Strain measuremants.

2. Secondary: The transducer which converts the output of first transducer into an electric output called Secondary transducer.

1. LVDT: Used to measure displacement, Force, Pressure and position.

2. Based on the power type

1. Active: Which do not recuire any power sources for their operation. They work on energy conversion principle. They produce an electrical signal proportional to the input[ Physical quantity ].

1. Thermocouple: Used to maesure Temperature, Radiation and Heat flow.

2. Photovoltaic Cell: Used in light meter and solar cell.

2. Passive: Which recuire an external power source for their operation. They produce an output signal in the form of some variation in resistance, capacitance or any other electric parameter. Which than has to be converted to an equivalent current or voltage signal.

1. Photocell [ LDR ]

2. Capacitive transducers: Used to measure liquid level.

3. Resistive transducers: Used to measure Temperature, Pressure, Displacement.

4. Inductive transducer: Used to measure Pressure, Vibration, Position, Displacement etc.

 3. Based on the the type of output

1. Analog: The transducer which produces their outputs in analog form. A form which continuous function of time.

1. Strain gauge: Used to mearsure Displacement, Force and Torque.

2. Thermistor: Used to mearsure Temperature and Flow.

2. Digital: The transducer which producess their output in digital form. A form of pulses.

1. Turbine meter: Used to mearsure Flow. 

4. Based on the electrical phenomenon

1. Resistive: Change in resistance of these sensors when certain physical quantity is applied to it.

1. Resistance thermometer: Used to measure Temperature and Radiant Heat.

2. Potentiometer device: Converts the change in displacement into change in the resistance.  Used to mearsure Displacement and Pressure.

3. Thermistor: Used to mearsure Temperature and Flow.

2. Capacitive: The change in distance between the two plates produced by the displacement results in change in capacitance.

1.Dielectric gauge: Used to measure Thickness and Liquid Level.

2. Capacitor microphone: Used to measure Noice, Speech and Music

3. Indutive:

1. Reluctance Pick-up: Used to mearsure Pressure, Vibration, Position, Displacement.

2. Eddy current gsuge: Used to mersure Sound, Force, Pressure.

3. LVDT: Used to measure displacement, Force, Pressure and Position.

4. Photoelectric: Converts light beam into a usable electric signal. Used to mearsure light intensity.

5. Photovoltic: Used to Photovoltaic cell and Photographic work.

5. Based on the non-electrical phenomenon

1. Linear displacement

2. Rotary displacement

6. Based on transduction

1. Transducer: A mearsuring device which measures and converts non-electrical variable into electrical variable.

1. Thermocouple: Used to maesure Temperature, Radiation and Heat flow.

2. Inverse transducer: A measuring device which measures and converts an electrical variable into non-electrical variable.

1. Piezo-electric crystal: Used to measure Pressure, Vibration and Acceleration.

Photoconductive Transducers:

Used to maesure Radiation at all Wavelengths.

Ionization Transducer:

Converts displacement to a voltage through capacitance change. Used to measure stedy magnetic field.

Hall-Effect Transducers

Digital Displacement Transducers:

Used to measure angular and linear displacements.