ACS712 Hall Effect Current Sensor Module — 5A / 20A / 30A
The ACS712 current sensor module measures AC and DC current using a Hall effect chip, with no need to break the circuit under test — current passes through the on-board conductor and the chip reads the resulting magnetic field. Three variants cover different ranges: 5A (185mV/A), 20A (100mV/A), and 30A (66mV/A). The analogue output connects directly to an Arduino or ESP32 ADC pin and reads in under 5 microseconds.
- Hall effect measurement — galvanically isolated, no series resistance in the current path
- Three range options — 5A, 20A, or 30A to match your application
- Analogue voltage output — VCC/2 (2.5V) at zero current, linear response across full range
- 5V supply, 5V logic — direct connection to Arduino Uno ADC
- 80kHz bandwidth — fast enough to measure motor inrush current
| Specification | Value |
|---|---|
| Chip | ACS712ELC |
| Current range | +/-5A / +/-20A / +/-30A (select variant) |
| Sensitivity | 185mV/A (5A) | 100mV/A (20A) | 66mV/A (30A) |
| Zero-current output | VCC/2 (approx. 2.5V at 5V supply) |
| Bandwidth | 80kHz |
| Supply voltage | 4.5V - 5.5V |
| Measures | AC and DC current |
How accurate is the ACS712 current reading?
Accuracy depends heavily on the ADC resolution of your microcontroller. On an Arduino Uno (10-bit ADC, 5V reference), you can resolve approximately 24mA per ADC step on the 5A variant. Adding an ADS1115 16-bit ADC reduces the minimum detectable current to under 1mA. Noise in the supply rail is the most common source of drift — a 100nF decoupling capacitor on the VCC pin reduces it significantly.
Does it measure AC as well as DC?
Yes. For AC measurement you sample the output rapidly and calculate RMS in software. For DC the output voltage is proportional to current with a simple linear equation: I = (Vout - 2.5V) / sensitivity.
Best for
Arduino motor current monitoring, battery charge/discharge measurement, solar panel output logging, 3D printer stepper motor diagnostics, ESP32 energy meters, mains AC monitoring (with appropriate isolation precautions), and robotics overcurrent protection circuits.
Why Kunkune
Shipped from UK stock. 60-day returns and no minimum order — buy the variant you need without committing to a multipack. Fast Royal Mail delivery.
For transformer-based galvanic isolation and better linearity at low currents, the ZMCT103C current sensor is an alternative approach to AC current measurement.
Buying in bulk? For orders of 10+ units or trade pricing, contact us for a custom quote.
