Current Sensor AC/DC Module with Analog Output ACS712 30A

Specifications

• Sensor IC: Allegro ACS712
• Current Range: -30A
• Sensitivity: 66 mV/A
• Operating Voltage (VCC): 5.0V DC (Nominal)
• Zero Current Output: VCC / 2 (Typically 2.5V at 5V VCC)
• Internal Resistance (Conductive Path): 1.2 mΩ (Ultra-low power loss)
• Isolation Voltage: 2.1kV RMS (Safe separation between high-voltage load and low-voltage logic)
• Response Time: 5µs
• Operating Temperature: -40°C to 60°C
• Dimensions: 31mm x 13mm

Applications

• Smart Home Energy Meters: Monitor the real-time AC current draw of household appliances.
• Solar & Battery Systems: Track charge/discharge rates in DC battery banks or solar arrays.
• Motor Control & Protection: Detect overcurrent situations or stall states in high-torque DC/Stepper motors.
• Power Supplies: Build custom benchtop power supplies with digital current readouts.

Unlock New Capabilities

• Past Projects: If you've mastered basic voltage dividers or simple relay switching, you're ready to upgrade.
• Feature Upgrade: This ACS712 module unlocks closed-loop control. Instead of just turning a motor on, you can now know how hard it's working and automatically shut it down before it burns out.
• Effort/Requirements: Intermediate. You'll need a basic understanding of analog-to-digital conversion (ADC) and standard math in your code. For AC current, you'll need to calculate RMS values using software.

Virtual Technician & Wiring Guide

• ⚠️ Safety Warning: While the IC provides isolation, you are still bringing potentially lethal voltages (like mains AC) to the screw terminals. Always ensure power is disconnected before wiring the load, and never touch the underside of the module when live!
• VCC: Connect to 5V on your microcontroller.
• GND: Connect to Ground.
• OUT: Connect to an Analog Input pin (e.g., A0 on Arduino). Because the output swings up to 5V, this is Probots Logic-Safe for 5V boards like Arduino Uno, but requires a simple voltage divider if you are using 3.3V logic boards like the ESP32 or Raspberry Pi Pico to prevent damage to their ADC pins.
• Screw Terminals (IP+ / IP-): Connect these in series with the load you want to measure (cut the live wire and put this sensor in the middle of the break).

Package Includes:

• 1 x Current Sensor AC/DC Module with Analog Output ACS712 30A

Frequently Asked Questions (FAQ)

• How does the ACS712 30A measure AC and DC current?
  It uses the Hall effect. The current flowing through the copper path generates a magnetic field, which the internal sensor converts into a proportional analog voltage.
• What is the sensitivity of the 30A version?
  The 30A model outputs 66 millivolts (mV) for every 1 Amp of current that passes through it.
• What is the zero-current output voltage?
  When exactly 0 Amps are flowing, the OUT pin rests at exactly half of the supply voltage (typically 2.5V when powered by 5.0V).
• Can I use the ACS712 30A with a 3.3V microcontroller like an ESP32?
  The OUT pin can reach up to 5V. To protect a 3.3V microcontroller's ADC pin, you must use a voltage divider (two resistors) to scale the 0-5V signal down to 0-3.3V.
• Why is my ACS712 output fluctuating wildly when measuring AC current?
  Because AC current alternates, the analog output is a sine wave oscillating around 2.5V. You cannot take a single reading; your code must sample the wave rapidly and calculate the Root Mean Square (RMS) value.
• Does this module provide electrical isolation?
  Yes, the conductive path is physically isolated from the logic pins, providing up to 2.1kV RMS isolation.
• What is the maximum voltage I can pass through the measurement terminals?
  The isolation allows it to safely measure current on 120V/240V AC lines, but exercise extreme caution with the exposed solder pads on the PCB.
• How do I calculate the DC current from the analog voltage?
  Formula: Current in Amps = (Measured Voltage - 2.5V) / 0.066V.
• Why is my sensor showing a non-zero current when nothing is connected?
  This usually happens if your VCC is not exactly 5.0V (which shifts the 2.5V center point) or due to nearby magnetic interference. You should calibrate the zero-point in your code.
• How do I filter out noise from the ACS712 output?
  You can add a small capacitor (usually 1nF to 10nF) to the filter pin on the IC if you are modifying the board, or use software-based moving average filters in your code.
• What is the power supply requirement for the ACS712?
  It requires a stable 5.0V DC supply. Using a lower or fluctuating voltage will drastically skew your readings.
• Can it measure both positive and negative DC current?
  Yes. Current flowing one way will increase the voltage above 2.5V, and current flowing the opposite way will decrease it below 2.5V.
• Is the ACS712 30A suitable for measuring very small currents (under 1A)?
  No. Because the resolution is only 66mV/A, small currents will get lost in ADC noise. Use the 5A version (185mV/A) for smaller loads.
• What gauge wire should I use for 30A on the screw terminals?
  For continuous 30A loads, you should use at least 10 AWG wire to prevent overheating at the terminals.
• Can the ACS712 module be used on a breadboard?
  The 3 logic pins (VCC, OUT, GND) can be plugged into a breadboard. Never pass high current (the IP+/IP- side) through a breadboard, as it will melt.