# AC current sensor module, 5A, ZMCT103C

> AC current sensor module ZMCT103C based on a toroidal current transformer for non-invasive measurement of 0-5A AC. Powered by 5V DC, analog output AO centered at ~2.5V and digital output DO with adjustable threshold via onboard potentiometer. Compatible with Arduino, ESP8266, ESP32, STM32. Accuracy ±1%, frequency 50-60Hz, operating temperature -40 to +85 degrees C, dimensions approx. 31x13mm. Suitable for power monitoring and overcurrent protection.

- Page: https://sigmanortec.ro/en/ac-current-sensor-module-5a-zmct103c
- Price: 8.88 RON
- Availability: In stock; 1-2 zile
- Reference: 33170 · EAN: 5948895470438
- Category: Mechatronics and IoT > Sensors and Modules > Voltage and Current Sensors
- Specifications: Nominal Current: 5 A; tension: NEEDLE
- Package (shipping data): 0.011 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 02:57 (Europe/Bucharest)

## Description

Ideal for monitoring consumption in DIY and automation projects, this module measures alternating current up to 5A and provides an easy-to-read analog signal with Arduino or other development boards. It integrates quickly into measurement circuits, has compact dimensions for easy mounting, operates stably in industrial and electronic applications, being suitable for load detection and energy control.
The AC current sensor module with ZMCT103C is a compact and efficient solution for measuring alternating current in light embedded and industrial applications. It is based on a precision current transformer with a toroidal core, which allows non-invasive measurement of alternating current without interrupting the tested circuit.
The module includes an integrated operational amplifier that conditions the output signal, making it directly compatible with the analog inputs of Arduino, ESP8266, ESP32, STM32 boards, and similar devices. The measurement range is 0 - 5A AC, with an analog output proportional to the measured current, calibrated for a 5V reference voltage.
It also features a digital output that switches when the current exceeds the set threshold. The trigger threshold of the digital output is adjusted via a potentiometer integrated on the board, allowing direct sensitivity adjustment without software.
The sampling resistor is included on the board, and the output is centered at approximately 2.5V when no current is present, allowing reading of both the positive and negative half-cycles.
Its small dimensions and mounting hole allow easy integration into panels and electronic enclosures. The module is suitable for energy consumption monitoring, overcurrent protection, industrial automation, and DIY projects involving the measurement of AC electrical loads.
Specifications:
Sensor type: ZMCT103C current transformer
Measurement range: 0 - 5A AC
Supply voltage: 5V DC
Output voltage: 0 - 5V analog (centered at ~2.5V without current)
Digital output: HIGH/LOW depending on set threshold
Threshold adjustment: potentiometer integrated on the board
Operating frequency: 50 - 60 Hz
Accuracy: ±1%
Sampling resistor: included on the board
Interface: analog output (pin AO)
Operating temperature: -40 to +85 degrees Celsius
Dimensions: approximately 31 x 13 mm
Pinout:
Pin
Signal
Description
VCC
Power
5V DC
GND
Ground
Common reference
AO
Analog
Analog signal proportional to current
DO
Digital
HIGH/LOW when exceeding set threshold
Usage:
Connect VCC to the 5V pin of the development board.
Connect GND to the common ground of the circuit.
Connect AO to an analog input pin of the board (e.g., A0 on Arduino) if you want the exact current value.
Connect DO to a digital pin of the board if you only want detection of current threshold exceedance.
Pass the AC load's phase wire through the sensor's toroidal hole. Do not connect the sensor directly to the mains, but to the wire supplying the monitored load.
Adjust the potentiometer on the board to set the current threshold at which the digital output DO switches. Turn clockwise to increase the threshold and counterclockwise to decrease it.
In the acquisition code, read AO for the RMS current value or monitor DO for overcurrent alarm and protection.
For the RMS value on AO, collect samples over at least one full cycle (20ms at 50Hz) and apply the RMS formula.
Calibrate the sensor by comparing the measured value with a reference device and apply a correction factor if necessary.