ACS712 20A Hall Effect AC/DC Current Sensor Module – Analog Output

The ACS712 20A Hall Effect Current Sensor Module is designed for measuring both AC and DC current up to ±20A and providing a proportional analog voltage output that can be read by a microcontroller or ADC.

Based on the ACS712 Hall-effect current sensor IC, the module provides electrical isolation between the high-current measurement path and the low-voltage signal circuitry. It is suitable for Arduino, ESP32 with appropriate ADC precautions, power-monitoring systems, battery projects, motor-current monitoring, chargers, power supplies, and automation applications.

Technical Specifications

• Sensor IC: ACS712
• Sensor Type: Hall Effect Current Sensor
• Current Measurement Range: ±20A
• Current Measurement: Bidirectional
• Supported Current: AC and DC
• Supply Voltage: 5V DC
• Output Type: Analog Voltage
• Sensitivity: 100mV/A typical
• Zero-Current Output: Approximately VCC/2, typically around 2.5V with a 5V supply
• Bandwidth: Up to 80kHz
• Response Time: Approximately 5µs
• Internal Conductor Resistance: Approximately 1.2mΩ
• Operating Temperature of ACS712 IC: -40°C to +85°C
• Connection: High-current terminals + VCC / OUT / GND signal interface
• Measurement Principle: Hall Effect

Bidirectional Current Measurement

The ACS712-20A can measure current flowing in either direction through its primary current path.

With a 5V supply, the analog output sits at approximately 2.5V when no current is flowing.

For the 20A version, the output changes by approximately 100mV for every 1A of current.

For example:

0A → approximately 2.5V
+10A → approximately 3.5V
-10A → approximately 1.5V

Actual values can vary slightly due to sensor tolerance, temperature, supply voltage, noise, and calibration.

AC & DC Current Sensing

The sensor can be used for both DC and AC current measurement.

For DC current, the controller can determine both the magnitude and direction of current from the analog output.

For AC current, the microcontroller samples the changing output waveform and can calculate the corresponding RMS current in software.

Microcontroller Integration

The analog output can be connected to an ADC-equipped controller such as an Arduino.

When using an ESP32 or another 3.3V microcontroller, special attention must be paid to the ADC input-voltage limit because the ACS712 module normally operates from 5V and its output can rise above 3.3V.

A suitable voltage divider, signal-conditioning circuit, or other ADC protection method may therefore be required.

Applications

Ideal for AC/DC current monitoring, battery systems, motor-current measurement, power supplies, solar projects, chargers, energy-monitoring systems, robotics, automation, overcurrent monitoring, load detection, Arduino projects, and IoT power-monitoring applications.

Important Note

The 20A specification represents a bidirectional measurement range of approximately -20A to +20A, not a recommendation to continuously operate every generic ACS712 module at 20A.

The ACS712 IC uses a very low-resistance internal current conductor, but PCB terminal quality, copper thickness, connector rating, ambient temperature, and cooling can affect the safe continuous current of the complete module.

For accurate measurements, software calibration of the zero-current offset and sensitivity is recommended.

Safety Note

The ACS712 IC provides galvanic isolation between its primary current path and signal circuitry, but the safe working voltage of a complete module also depends on the PCB layout, creepage distance, terminals, connectors, and overall module construction.

Do not assume that a generic ACS712 breakout board is automatically safe for direct mains-voltage measurement solely because the sensor IC has a high isolation rating.

When working with mains voltage, use appropriately designed equipment and proper electrical safety procedures.

Package Includes

1 × ACS712 20A Hall Effect AC/DC Current Sensor Module