How to measure AC current and DC current with ACS712 in Simple Steps.


How does the ACS712 work?

How to connect ACS712 to Arduino?

How to measure AC current with ACS712?

How to measure DC current using ACS712?

What is the sensitivity of the ACS712?

What is the output voltage of ACS712 at 0A?

How to calculate current from voltage using ACS712?

How accurate is ACS712?

Can ACS712 measure bidirectional current?

How to convert ACS712 output to real-time current?

Why is my ACS712 output noisy?

Can ACS712 be used for high voltage applications?

What is the maximum current ACS712 can detect?

What is the difference between ACS712 5A, 20A, and 30A modules?


ACS712 Arduino

ACS712 wiring

ACS712 code

ACS712 5A 20A 30A

ACS712 calibration

ACS712 output voltage

ACS712 sensitivity

ACS712 AC current

ACS712 DC current

ACS712 datasheet

ACS712 RMS calculation

ACS712 analogRead

ACS712 Hall effect sensor

ACS712 noise filter

ACS712 code



The ACS712 is a Hall-effect-based linear current sensor developed by Allegro MicroSystems. It provides accurate and isolated current sensing for both AC and DC currents in various applications.

 Key Features


Current Sensing Range: Available in 5A, 20A, and 30A variants.
Output Sensitivity:

185 mV/A for the 5A model
100 mV/A for the 20A model
66 mV/A for the 30A model

Supply Voltage: Operates on a single 5V supply.
Output Voltage: Provides an analog voltage output centered at VCC/2 (typically 2.5V) when no current flows.
Isolation Voltage: Offers 2.4 kVRMS isolation between the sensed current and the output signal.
Bandwidth: Up to 80 kHz, adjustable via an external capacitor on the FILTER pin.
Low Noise: Features a low-noise analog signal path with chopper stabilization for minimal offset drift.
Package: 8-pin SOIC with integrated low-resistance current conductor.


 How It Works


The ACS712 utilizes the Hall effect to measure current. When current flows through the integrated conductor, it generates a magnetic field. The Hall sensor detects this field and converts it into a proportional voltage. This voltage is then amplified and output as an analog signal. The device's chopper-stabilized amplifier ensures accurate and stable readings over temperature variations .

 Applications


Motor Control: Monitoring and controlling motor currents in industrial applications.
Power Supplies: Current sensing in switched-mode power supplies (SMPS).
Overcurrent Protection: Detecting and responding to overcurrent conditions.
Battery Management: Monitoring charge and discharge currents in battery systems.
Arduino Projects: Integrating with microcontrollers for DIY electronics projects .

 Integration Tips

FILTER Pin: Connecting a capacitor to this pin can adjust the bandwidth and reduce noise.
Calibration: For precise measurements, calibrate the sensor in your specific application setup.
Temperature Considerations: Be aware of potential output drift with temperature changes; consider implementing temperature compensation if necessary.


Using the ACS712 current sensor with an Arduino is a common and effective way to measure AC or DC current in electronic projects. Here's a complete guide to help you get started:

 Wiring the ACS712 with Arduino


 Parts Required

ACS712 module (5A / 20A / 30A variant)
Arduino Uno (or compatible board)
Load (e.g., a DC motor or lamp)
Power supply (for the load)
Jumper wires


 ACS712 Pinout


Pin Description

VCC Connect to 5V on Arduino
GND Connect to GND on Arduino
OUT Connect to Arduino analog pin (A0)
IP+ / IP– Current input terminals (for load)



 Wiring Diagram

LOAD + ----> IP+ (ACS712) IP– ----> Power Supply +
--> Arduino A0 (OUT)
ACS712 VCC ---> Arduino 5V
ACS712 GND ---> Arduino GND

 How It Works

The sensor outputs 2.5V when no current flows.
Output voltage increases or decreases based on the direction and magnitude of current.



The change in voltage is proportional to current:

5A model: ~185 mV/A
20A model: ~100 mV/A
30A model: ~66 mV/A



 Arduino Code Example


const int sensorPin = A0;
const float Vref = 2.5; // No-current voltage (centered at 2.5V)
const float sensitivity = 0.185; // For 5A module (V per Amp)

void setup() {
Serial.begin(9600);
}

void loop() {
int adcValue = analogRead(sensorPin);
float voltage = adcValue * (5.0 / 1023.0);
float current = (voltage - Vref) / sensitivity;
Serial.print("Current: ");
Serial.print(current, 3);
Serial.println(" A");
delay(1000);
}


 

Adjust sensitivity for your module:

5A: 0.185
20A: 0.100
30A: 0.066

 Tips for Accurate Measurement

Use averaging (read multiple samples).
For AC current, compute RMS.
Add a low-pass filter capacitor to the FILTER pin (optional).
Ensure proper isolation from high current paths.

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