Why three wire is using with a RTD?

Answer Posted / guest

Resistanc Temperature Detector(RTD)encorporates two basic
concepts

1)Variation of temperature varies the resistance of Pt wire.
2)Variation in resistance affects the balancing of DC
bridge circuit.

For measurement purposes lead wires are brought out to make
external connections.These lead wires have some resistances
which affects the bridge balancing.

Since we can not reduces the resistances of lead wire to
zero.So, either 3 wire or 4 wire connection is employed to
ELIMINATES THE IMBALANCING TO THE BRIDGE CIRCUIT caused by
resistances of lead wires so that an accurate measurement
can be made.These wires(3 or 4) are called compensating
leads.

Author:arbelectbit@yahoo.com

Is This Answer Correct ?    29 Yes 4 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

the output of the common trasmitter protocol in qatar gas are the following

1549


What should be the main consideration while starting the Rotating compressor when we dont know the cut in and the cut off pressure setting of the pressure switch

1681


In turbine what does term CDP, NI, NH, HSSOC means.

2022


What is Span Error

196


What are de-saturators?

719






Operational amplifiers

1512


I want to know about DDCMIS in detail ? please explain it. Also give name of reference books in which it is explained in detail in very simple manner.

3292


1.what is the effect of vapour presuure in orifice plate flow measurement 2.which is more effective 2 pressure sensors or one single differential pressure sensor in orifice plate measurement 3.how to design a v/i converter and i/v converter 4.how many type of thermocouple are there 5.how many leads are there in thermocouple measurement 6.how pressure sensors are connected in level measurement in differential pressure method 7.what is the output of capacitive pressure sensor (ac or dc),how its o/p is signal charactarized 8.what is the physical meaning of discharge coeeficient,why it is calculated,orifice plate what is its value,why it is less than 1,Q at upstream is equal to or not equal to Q at downstream of orifice plate why?what is vena contracta in orifice plate 9.why rotameter is called variable area flowmeter,it can measure flow even if area is not varying,why it is made tapered 10.design a 10 bit counter ,which counter you will prefer 11.how to remove self heating error in RTD 12.which is more sensitive pt100 or pt50 13.why thermocouple are connected in parallel 14.what is lead contact error in RTD,how to avoid 15.what is P,PI,PID,PD controller,why there is no ID controller 16.what is override,split range,sequential,ratio,feedforward,cascade controller 17.why we moved from SR to JK and then JK to master slave JK flipflop,give correct reason 18.how to measure level of a closed container which contains vapour and liquid,remember no vapour gas should be leaked,so ultrasonic and capacitive is not an option,design another method 19.how to design horse race counter including sensors and signal conditioning element 20.what is bevelling

1947


Please any one can provide latest aptitude test,technical test and interview questions for tata consulting engineering (TCE) i need it asap thanks in advance

1547


why we are using digital signals for I/O & how to measure this signals is getting or not ?

1528


Why trim span ? How?

1065


How to do gas analysers calibration in AUTO and Manually by using zero and span gas?

1914


what is cems analyzer explain with principle and drawing ?

1856


what is IEC code in cables & how to selecting cables?

1280


Calibration procedure for Electro magnetic Flow meter

4025