why we are called the 4-20ma transducer,not 0-20 ma transducer??

why we are called the 4-20ma transducer,not 0-20 ma
transducer??

Question Posted / arjun

3 Answers
5794 Views
I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / praveen kumar gupta

4mA is the minimum operating current of controling device

Is This Answer Correct ?

2 Yes

0 No

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / vaseekaran

Let us keep the value as 0 to 20 mA,
The valve we measure in the output will be zero if the meter is in idle state and also it will show the same zero even the instrument is in fail condition.so we cannot get the exact and get confused if there is a problem in instrument while cross checking.this is the reason we are using 4 to 20mA.if the instrument fail then we can get only zero and if the instrument is idle we will get 4mA.so we can easily differentiate it.

Is This Answer Correct ?

2 Yes

0 No

why we are called the 4-20ma transducer,not 0-20 ma transducer??..

Answer / raja

There is a long tradition dating from the early pneumatic
instruments for a control range from 25% to 100%. If you
want to know why, look at the pressure vs travel curve for a
flapper-nozzle. The early electronic instruments used the
same force-balance approach (many with a 10-50 mA range -
easier to get a higher force with the higher current) which
was eventually translated over into the pure electronic format.

Is This Answer Correct ?

0 Yes

0 No

Post New Answer

More Electrical Engineering Interview Questions

what is the current generated in a 230v megger?

2 Answers

What effect of supplying stationary generator (800kVA) with 415V AC from 1500kVA transformer?

2 Answers

please let me know , we have installed two separate motor for fire fighting system 1) 60 hp and 2) 15 hp the load is 74 AMPS and 20 AMPS then tell me the main power cable in Aluminum will be what thickness , the length is 225 mt from the main utility to fire pump house

1 Answers

How to calculat size of copper & aluminium ?

6 Answers

what is the difference between transformer and amplifier ??

5 Answers

What does ampere turns shows?

0 Answers

what happens in a genarator when rotor supplied with ac instead of dc

3 Answers

Why fuel tanks to be earthed ?

6 Answers Electronics, Hindustan Petroleum, HPCL, Ispat,

what is harmonics?