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# ADC Accuracy vs Precision

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#### hioyo

##### Advanced Member level 4
May I know the difference between ADC Accuracy and precession.

Can I say accuracy is a measure of how close the actual measurements to ideal measurements

and precision is the number of distinguishable ADC inputs.

Solution
Hi,

you may do in internet search "accuracy vs precision". You may find many good explanations.

In short: both are measures of multiple conversions.

let´s say your analog input is 1.000V and the digital values of lets say five values represent:
* 1.05V, 1.04V, 9.97V, 9.99V, 9.96V (average = 9.998V)
this means high accuracy. The average of the 5 conversions is very close to the target. Accuracy error just 2mV. But some value is off +50mV, the other -40mV. Thus the precision error is about +-/50mV
(good accuracy, mediocre precision)

other 5 values:
* 1.09, 1.08, 1.08, 1.08, 1.09
Here the accuracy is about 80mV off, but the precision is rather good.
(bad accuracy, good precision)

Accuracy: how close the (average) value is at the...
precision is the repeatability of a measurement - that is, if you take many measurements, how close are they to each other.

accuracy is the correctness of a measurement - that is, if you take many measurement, how correct are they are

Hi,

you may do in internet search "accuracy vs precision". You may find many good explanations.

In short: both are measures of multiple conversions.

let´s say your analog input is 1.000V and the digital values of lets say five values represent:
* 1.05V, 1.04V, 9.97V, 9.99V, 9.96V (average = 9.998V)
this means high accuracy. The average of the 5 conversions is very close to the target. Accuracy error just 2mV. But some value is off +50mV, the other -40mV. Thus the precision error is about +-/50mV
(good accuracy, mediocre precision)

other 5 values:
* 1.09, 1.08, 1.08, 1.08, 1.09
Here the accuracy is about 80mV off, but the precision is rather good.
(bad accuracy, good precision)

Accuracy: how close the (average) value is at the target.
precision: = repeatability. How much the values differ from one to the other.

Klaus

hioyo and d123

### hioyo

Points: 2
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Generally accepted definitions, Meteorological :

Other :

Regards, Dana.

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hioyo

### hioyo

Points: 2
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Hi,

while I like the "ametsoc" definitions ...I don´t like the "accuracy" definition in the Wikipedia page. And I miss the "precision" definition in the Wikipedia page at all.

Klaus

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