why we use 4-20 mA to do calibration of the instruments.why
we cant use 0-20 mA?

Answer Posted / sathish r

Module require 1-5 v for further processing thats why we
use 4 - 20 mA because with 250 ohms resistance we can
easily convert 4 - 20 mA into 1 - 5 V

.004 A x 250 ohms = 1 V
.02 A x 250 ohms = 5 V

if we use 0 - 20 mA it converts 0 - 5 v but we required 1 -
5 v for further processing in module.

Is This Answer Correct ?    9 Yes 19 No



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