acs712 05B amplify - range 3A

128

01:42:02

acs712-05B should produce 185mV each ampere; here I'm interested to a range of 0-3A so the purpose of amplification here is to increase the divisions that adc can see and for arduino is 1024 over a 0-5V range.

Follow lab results where Vin is the voltage produced by acs712, V1 is the voltage after first opamp stage (filtered), V2 is the voltage after second opamp stage.

LAB RESULTS
============
without filter I had Vpp of 0.8 while filtering Vpp reduces to 0.1

using current = 0 ; 1 ; 2 ; 3 (A)

VOLTAGES
Vin = 2.51 ; 2.67 ; 2.83 ; 2.99
V1 = 0 ; 0.48 ; 0.97 ; 1.46
V2 = 0.3 ; 1.21 ; 2.27 ; 3.24

SLOPES
Vin = 0.16 ; 0.16 ; 0.16
V1 = 0.48 ; 0.49 ; 0.49
V2 = 0.91 ; 1.06 ; 0.97

FEATURES ( sensibility ; divs ; resolution )
Vin ( 160mV/A ; 98divs ; 30.5mA )
V1 ( 487mV/A ; 299divs ; 10.03mA )
V2 ( 980mV/A ; 602divs ; 4.98mA )

published 6 years ago

hurz

6 years ago

i see it without amplification as advantage, cuz i can this directly apply to e.g. arduino ADC. What is the advantage of your +-5V if its for arduino a step back. Where do you need this? Always think of both directuons sink and source current so above 2.5V or below.

devel0

6 years ago

thx for your feedback hurz, I used only positive part of AC generator in my mind, but effectively I could represent my 2.5V to 2.5V+0.925V signal using an AC with DC2.96V and amplitude of 0.925V/2 ; the circuit remain the same. The amplification of course if used to retrieve current 0-5A with better 5x resolution because without that on 1V with arduino std adc I would get 205 divisions instead of 1024 within a resolution of 5A/205=24mA instead of 5A/1024=4.9mA ; more for my need ( a solar panel 30W with Isc=1.83A a 3A range will enough ) so I will clone this project for that purpose with amplification that takes in account an input voltage of 2.5 to 0.185V*3~=3V to obtain a resolution smaller than 4.9mA

hurz

6 years ago

would be nice to have this all in description, and i wont ask for.

devel0

6 years ago

Hi hurz, I'm newbie in electronics so any feedback are valuable to me, I would like to know your opinion about this latest config, I will try in lab to see if it works in the real.

hurz

6 years ago

You are welcome!

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