Where to Buy?

This CT is available in many Chinese online websites as well as Amazon. Its price varies, but you can get it for approximately $0.6 in most stores.

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My personal favrate for this product is Aliexress (get 3$ coupen for new user) Slow Shipping but Low Price + Wolrdwide Delivery.

ZMCT103C AC current Sensor is the best for the purpose of the DIY project and industrial application, where we need to measure the accurate AC current with current transformer. This is an perfect choice to measure the AC current using Arduino/ESP8266/Raspberry Pi like an opensource platform. In many electrical projects, engineer directly deals with measurements with few basic requirements like

  • High galvanic isolation
  • High accuracy
  • Good Consistency

This is a high precision micro current Transformer. This module makes it easy to monitor AC mains current upto 5 Amps . ZMCT103 is  a pcb mount current transformer with 1000:1 turns ratio and Dimensions: 28 x 12 x 15 mm(LxWxH).

Applications of ZMCT103C Current Transformer

  • Metering (electrical energy meters)
  • AC Voltage measurements
  • Sensing Overload Current
  • Ground fault detection
  • Household electrical equipment
  • Industrial apparatuses
  • Electrical testing equipment and relay protection
  • Analog to digital circuits      

Features of ZMCT103 Micro Precision Current Transformers

  • low price
  • small size ( 18.3mm x17 mm) and lightweight
  • Easy PCB mounting
  • Good consistency
  • widely acclaimed
Specifications Discriptions
Rated input current 0-10A(50Ω)
Rated output current 5mA at input 5A
phase angle error ≤15'(input 5A,sampling resistor 50Ω)
Isolation withstand voltage 4500V
Turns Ratio 1000:1
Measurement accuracy Class 0.2
Linearity ≤0.2%(5%dot~120%dot)
Installation PCB mounting(Pin Length>3mm)
Operating Frequency 45-55Hz
operating temperature -40℃~+85℃

Know More About pcb mount current transformer

ZMCT103 is a high precision Current Transformer. This module makes it easy to monitor AC mains current upto 5A. A tiny little thing the size of a bouillon cube. Holds up to 4.5kV per breakdown voltage, the ratio of turns is 1000: 1, but this is a current transformer of 5A: 5mA.

ZMCT103C Datasheet

Download the datasheet of ZMCT103C it provide details specification, dimensions, mounting etc.

ZMCT103C Arduino Wiring Diagram

To connect a ZMCT103C sensor to an Arduino board, the output signal from the ZMCT sensor needs to be convert into measurable range of  Arduino analog inputs, that is +ve voltage between 0V and the ADC reference voltage (5V is no ADC Reff is supplied).  The sampling of current sensor signals is done by Arduino code given below.

To do this job the following circuit is used,

ZMCT103C Micro Current Transformer | 5A / 5m | Arduino Code 1

The output of this CT is a current signal, which needs to be converted to a voltage signal using a burden resistor. See the circuit explanation and calculation of Burdon resistor are given hear  SCT-013

ZMCT103C Arduino Code

EmonLib.h” Electricity monitoring library designed by is best for voltage and current measurement usign Arduino Code.

During measurement using Arduino Code, the signal conductor to be passes through the current transformer hole, VCC and GND are connected to the 5V DC power supply, VOUT and GND are connected to the analog pin of Arduino.  this simple Arduino code uisng emonLib.h you will get praportional current output.
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Micro Current Transformer Module using ZMCT103C

The module is designed using the ZMCT series of small size high-precision micro CT and high-precision operational amplifier circuits for more accurate sampling and proper signal compensation. It is best solution for the signal acquisition of AC current within 5A range.

The corresponding output voltage analog AC signal can be adjusted using the potentiometer. You can adjust the amplification ratio and the amplification range ( 0-100 times), but the max voltage at the output will not more than half of  VCC applied voltage. The same Arduino code is useful to measure current using this module.

ZMCT103C module arduino

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Current Transformer PCB Mount Module 

The module is designed using On-board micro-precision current transformer and Onboard sampling resistor. all other specifications are the same.

ZMCT103C module arduino

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Application Projects Using ZMCT103C

Over-current Protection Sensor module using ZMCT103C


    • Working voltage: DC 5V / 12V/24V
    • Working current: <20mA
    • Temperature range: -40 ° C ~ + 85 ° C
    • Humidity: 0~95% RH
    • Size: 4.4×3.8cm / 1.73×1.5″
    • Frequency range: 20Hz~400Hz
    • Output mode: switching signal output

You could Select this overcurrent protection Module as you wanted, three different options are available.

  • 1 * 5A 5V Overcurrent Protecting Detection Sensor Module
  • 1 * 5A 12V Overcurrent Protecting Detection Sensor Module
  • 1 * 5A 24V Overcurrent Protecting Detection Sensor Module
ZMCT103C module arduino

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