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Introduction

Detector

Detector is a device used to sense the presence of something such as heat, radiation, orother physical phenomena.

Sensor

Sensor is a device used to detect, measure, or record physical phenomena such as heat,

radiation, and the like and to respond by transmitting the information, initiating changes,

or operating controls.

Transducer

Transducer is a device that converts one form of energy or Physical quantity to another.

Relationships between sensor and transducer

Sensor is sometimes called a primary measuring element, it can be found simply as a

mercury thermometer to measure the temperature. It may be embedded in the transducer

to perform its function. That means the transducer consists of a primary element (sensor)

plus a secondary element (signal conditioning circuit) that transforms the passive change

or small voltage signal into active signal range that can be easily used in other chains of

the control loop.

Example: with a resistance thermometer, the resistance depends on the temperature value

(sensor). It can be inserted into a bridge circuit (secondary element) in order to transform

the change in the resistance value to a change in the voltage output. Finally, the output

voltage from the bridge circuit express about the temperature change value. In general,

we can say that:

Transducer = Sensor + Signal conditioning circuit

Parameter Measurement in Sensors and Transducers

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Sensing Module:- is the first element to receive a signal from the measured mediumand

produces an output depending on the measured quantity. The measuredquantity gets

distributed by the act of measurement, good instruments are normally designed to

minimize the error of measurement.

Conversion Module:- Transducer Module - converts one physical variable toanother. Incertain cases, the transduction of the input signal may take place in stages such as

primary, secondary, and tertiary transduction.

Variable Manipulation Module:- usually involves signal conditioning; like amplifiers,

linkage mechanisms, gear boxes, . An electronic amplifier accepts a small voltage signal

as an input signal and generates a signal that is many times larger than the input signal.

Data Transmission Module: sends a signal from one point to another, the transmission

element could be shaft device or could be complicated such as transmitting signals from

ground to satellite.

Data Display module:- produces information about the measured quantity in a form that

can be recognized

Application of sensor,tranducer,detector: