First the question is not complete and clear. Which type of recorder you are talking about? Mechanical, Electronic (Analog or Digital), or Magnetic etc.

Any recorder record a variable quantity. May be physical- temperature, pressure, humidity, weight, speed, acceleration, voltage, current, power etc. etc. Now these physical quantities need to be converted to another physical quantity say mechanical movement, or voltage or current depending upon the type of recorder. This conversion of one physical quantity to other takes place through a mechanism or a device called transducer. Simple microphone is a transducer. It converts air pressure into equivalent varying voltages. Speaker is a transducer that converts varying voltages at its input into equivalent  varying air pressure.

A transducer transforms a signal into another, normally another that is proportional to the one you want to measure. Say you want to measure a force x. A strain gauge produces a voltage y that is proportional to x, (y=kx), so when you record y you will know what x is. Simple like that.

Hello Sir,

I found a hybrid recorder few days ago and it was mention that transducer is not used in this hybrid recorder. So, my actual query is, what is the exact reason behind this. what are the disadvantages of using transducer in hybrid recorders and what will be advantage if we use it.

What physical quantity your 'hybrid recorder' records?

Hello sir,

The hybrid recorder which i have is combination of monitoring and recording system.

Applications are:

Furnace monitoring for steel and metal processing, Remote control monitoring & recording of pump station, Flow leakage detection and alarm generation, Batch production and quality analysis, Gas and effluent emission recorder, Sterilisation & ultraviolet Disinfection processes recorder, Milk pasteurisation & other HACCP applications, Cold storage and transport of perishable goods with Data logger (mini-log), Pure water and waste water quality (pH, conductivity etc.) monitoring & recorder, Tank level monitoring and remote inventory management over modem

Limit overshoot, pump failure and event alarm over GSM messaging, Oven temperature monitoring & recording for Electric Manufacturing

If your hybrid recorder acquires all those physical quantities, I am pretty sure it does have 'transducers', as most (or all) of them will have to be 'transduced' to a voltage. Best wishes.

Dear sir,

You will use the standard signal transducer for every measuring values that provides   your hybrid recorder.

Dear sir,

I am unable to understand your point properly. So, can you explain little more. Thank You.

Anurag Pandey to whom you are addressing your request for more explanation?

As answered by Fernando Soares Schlindwein, its impossible to measure physical quantities without transducers. because all the "data/information" to be measured by our devices should be in the form of either voltage or current. and as these physical quantities themselves are not in voltage/current form, we need transducers to convert them to voltage/current proportional to physical quantities measure. 

Dear Fernando Soares Schlindwein Sir,

I was asking to Vasyl Yatsuk Sir for explaining more about his answer.

You will use such transducer as P30U temperature and standard signals transducer (http://www.oem.co.uk/products/Panel/Signal_Transducers/P30U_temperature_and_standard_signals_transducer/1159079-781601.html and similier type.

First the question is not complete and clear. Which type of recorder you are talking about? Mechanical, Electronic (Analog or Digital), or Magnetic etc.

Any recorder record a variable quantity. May be physical- temperature, pressure, humidity, weight, speed, acceleration, voltage, current, power etc. etc. Now these physical quantities need to be converted to another physical quantity say mechanical movement, or voltage or current depending upon the type of recorder. This conversion of one physical quantity to other takes place through a mechanism or a device called transducer. Simple microphone is a transducer. It converts air pressure into equivalent varying voltages. Speaker is a transducer that converts varying voltages at its input into equivalent  varying air pressure.

The transducer is a device which is used for converting one form of energy into another form. In general, transducers deal with different energy types such as electrical energy, mechanical energy, chemical energy, light energy, electromagnetic energy, thermal energy, acoustic energy, and so on. For example, consider mic (mic of telephone or mobile phone or audio set mic) we use in our day-to-day life converts the audio signals into electrical signals and then amplifies it into the desired range (depends on system and settings of the user). Then, converts the electrical signals into audio signals at the output of the speakers or loudspeaker. The fluorescent bulbs we use for lighting, converts the electrical energy into light energy. The mic, speaker, and fluorescent bulb can be considered as transducers. Similarly, there are different types of transducers used in practical applications.

Find this link to know about the sound transducers:

http://www.electronics-tutorials.ws/io/io_8.html

Transducers are used to convert different non-electrical signals into electrical signals. The physical quantities like temperature, pressure, speed, weight can be converted into electrical signal with the help of transducer. The accuracy of the recording system will be improved with the help of transducer. As abinayaa mentioned electrical signals can be amplified easily and processing of electrical signal is convenient than non-electrical signals

you can refer the following pdf, for the sensors used in a hybrid recorders.

http://dev.quasarusa.com/wp-content/uploads/2010/12/Matthews_ACI_2006_Novel-Hybrid-Sensors-for-Unobtrusive-Recording-of-Human-Biopotentials.pdf

That are the units for transform some physical quantities into standard electrical signal in general dc current in the range  0... 4 mA or 4...20 mA and/or dc voltage 0...10 V. This is enable to connect transducer output direct to recorder output. The recorder must have input appropriate to connect this electrical signal.