Difference between Sensor, Transducer and Transmitter

Hello everyone,

Now before starting the discussion of instrumentation system first let me distinguish the difference between sensor, transducer, and transmitter :

1. sensor -

A sensor that senses physical property like temperature, level, flow, pressure, humidity, concentration, etc. and convert it into a low level of electrical signal.now to measure properly or to send that signal over a long distance it used circuitry which amplifies a signal to send it over a long distance.

2. transducer -

Transducer which converts one form of energy to another form like i/p converter (current to pressure) or p/I (pressure to current) which used extensively with pneumatic valves where the signal needs to convert to perform a task.

3. transmitter -

Now most people think that transmitter only used to send a signal over long distance.yes this is right but also it maintains that proper mA current is proportional to applied pressure emphasized text. (i.e. let I have a transmitter which has a range from 0-6 bar has applied pressure let assume is 3 bar so it maintains that proportional current of 12mA Irrespective of applied voltage about till 12 v it hold its mA output.)

Let come to our topic :

Types of instrumentation used in industry

  1. Pressure Measurement

  2. Level measurement

  3. Temperature measurement

  4. Flow measurement

  5. Analytical measurement (PH, conductivity,etc.)

in the next post, I will explain each and everyone and type of each measurement.

hope you like this.


@suhel_patel Very useful topic (basics).

1 Like

Mr mehta,

Can you tell me from which you read all of the thing.sorry to say that your first two concept are totally wrong as you switched between sensor and transducer .kindly do google if you still feel that you are right.

Sensor are always convert that physical property to low level of electrical signal. Most sensor rely on transducer to convert measured signal into another form of signal. so transducer basically convert one form of energy to another form. In simple both have property of convert one energy to other form of energy but sensor always convert physical property into electrical signal. still you have doubt then ping me.

Mr. Mehta,

In transducer, I wrote with an example that i to p converter or p to i converter can you tell me what I (current) represent? If you understand I don’t think you need to ask another question.

Sensor is a device that when exposed to a physical phenomenon (temperature, displacement, force, etc) produces a proportional output signal (electrical, resistance, voltage, capacitance, inductance, mechanical, magnetic etc)

The term transducer is often used synonymously with sensors.

Sensor is a device that responds to a change in the physical phenomenon.

Transducer is a device that converts one form of energy into another form of energy.

Sensors are transducers when they sense one form of energy input and output in a different form of energy

Eg: a thermocouple responds to a temperature change (thermal energy) and outputs a proportional change in electromotive force (electrical energy)

The sensor outputs can be in any form like voltage, current, resistance, capacitance, etc.

Thermocouple - It is a temperature sensor and output in the form of milli volts.

RTD - It is also a temperature sensor and output in the form of Resistance.


Ok, I may be wrong take your time & let me know how you differentiate between sensor & Transducers.

  1. RTD
  2. Thermocouple
  3. Thermistor
  4. Piezoelectric crystal
  5. Bourden tube
  6. Diaphragm
  7. Vibrating fork
  8. LVDT
  9. Load cell ( strain gauges)
  10. MEMS
  11. Floats
  12. Air bubbler
  13. Flapper nozzel
  14. Glass gauges
  15. Radiation pyrometer
  16. Seger cones
  17. Color pellets
  18. Radar gauges
  19. Capacitive devices
  20. Inductive devices
  21. Eddy current devices
  22. Hall effect devices
  23. Gas chromatographs
  24. O2, N2 & CO2 analyzers
  25. Mass flowmeters
  26. DP meters
  27. Current meters & volmeters

Classify them which are sensors & Transducers with valid reasons.