why we use 4-20 mA for calibration of the instruments.why
we cant use 0-20 mA?
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Answer Posted / naveen
Logically Zero milli amps means no current in the circuit .
if we have an initial value to be measured , we cant measure
it as zero milli amps . It means no current in the circuit
or the circuit is open . so we go for the span of 4 to 20 mA
. this is coz we can easily split 4- 20 as multiples of four
(4,8,12,16) which means 0%,25%,50%,75%and 100% respectively.
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