Measure AC Current Using Arduino And SCT-013 Sensor

In this tutorial, we’ll show you how to measure AC current using Arduino and SCT-013 current transformers. this guide goes over how to use the SCT-013 current sensor with Arduino. This sensor is used to measure alternating current (AC) up to 100 amps. We’ll go over how to wire the sensor, how to get readings from the sensor, and how to calculate the current drawn from the sensor.

The SCT-013 current transformer is common in home energy meters. It is a component that measures the current in a wire without having to break the circuit.

Required Material

To measure AC current with Arduino, you will need the following components

• SCT-013 current sensor
• Arduino board
• Breadboard
• Jumper wires
• Load (for testing)

How does it work?

The SCT-013 current sensor operates on the principle of magnetic induction, which means that it can measure the current flowing through a wire without making physical contact with the wire itself.

It works based on the principle of magnetic induction, where a ferromagnetic core is used to detect the magnetic field generated by the current-carrying wire.

SCT-013 current sensor

The SCT013 sensors are instruments that help us measure the amount of electrical current flowing through a wire. without cutting or changing the wire. These sensors work by using a special technique called electromagnetic induction.

It works by detecting the magnetic field that is created by the current, and then converting that magnetic field into an electric signal that can be read by a microcontroller or other electronic device.

This makes it safe and easy to use, even for people who are not experienced with electronics. You can simply clamp it on and connect it to get the readings. The sensor can be connected to an Arduino or any microcontroller board to read the current values and use them for different purposes, such as monitoring power consumption or controlling a device based on current levels.

The SCT-013 is a convenient device that can be easily attached to either the live or neutral wire without any electrical work involving high voltage.

The sensor has a primary winding, a magnetic core, and a secondary winding. These are all composed of many Turns of fine Wire enclosed in the transformer casing.

SCT-013 current sensor Schematic

SCT-013 current sensor specs

Here are some specifications for the SCT-013 current sensor:

• Input Current Range: 0-30A AC
• Turns Ratio:  1800:1
• Non-linearity: <±3%
• Phase Shift: <±1°
• Operating Temperature: -25°C to +70°C
• Output Signal: AC voltage proportional to the input current
• Output Voltage at Rated Input Current: 1V (other values available depending on the model)
• Output connector: 3.5mm audio jack or 3-pin header
• Frequency Range: 50Hz – 60Hz
• Dielectric Strength: 6000V AC/1min
• Accuracy: Class 1 (IEC 61869)
• Dimensions: 50mm x 34mm x 25mm

Note – These specifications may differ on the manufacturer and model of the SCT-013 current sensor, so it is always important to refer to the datasheet for the specific specifications.

SCT-013 Current Sensor Application

1. Energy monitoring:
2. Power management
3. Renewable energy systems
4. Industrial automation

The SCT-013 current sensor is relatively simple to use and can be a helpful tool for hobbyists, students, or professionals working in fields related to electronics or electrical engineering.

SCT-013 current sensor Wiring

16×2 LCD Display

16×2 LCD (Liquid Crystal Display), is a type of display used in electronics to display numbers, letters, and in some cases, symbols. The screen is arranged into a 16×2 grid, each grid representing a pixel.

The display is built up of two rows containing sixteen characters each, hence the name “16×2“. Each character is made up of five by eight pixels, which can be used to display letters, numbers, and/or symbols. check the previous post  How to use 16×2 LCD With Arduino – Tutorial

Interfacing Current Sensor SCT-013 And Arduino

The Electricity Energy Meter using Arduino is a simple circuit diagram shown below.

The following connections are required:

• SCT sensor output pin to analog input pin A0 of the Arduino.
• LCD pins RS, E, D4, D5, D6, and D7 to digital pins 12, 11, 5, 4, 3, and 2 of the Arduino, respectively.
• LCD VSS pin to ground (GND) of the Arduino.
• LCD VDD pin to +5V pin of the Arduino.
• LCD V0 pin to a potentiometer, with the pins of the potentiometer connected to +5V and GND of the Arduino.

A 10K resistor and a 100-ohm resistor are required to complete the circuit. In addition, a 10uF capacitor is required.

How to calculate current drawn by an electrical device

To calculate the current drawn by the electrical device from the power supply, we can use the simplified formula:

I = P / E

Where I is the current in amperes (A), P is the power in watts (W), and E is the voltage in volts (V).

For example, if a device has a power rating of 2200 W and is attached to a power supply of 220 V, the current drawn would be 10 A (amperes), which can be calculated as follows:

I = P / E = 2200 W / 220 V = 10 A

The program we created was based on the resources and instructions provided by the Open Energy Monitor website, specifically the EmonLib library made for this type of sensor.

The library can be downloaded from the above link and should then be unzipped and put in the Libraries folder of the Arduino IDE.

Source code

To modify the voltage, adjust the variable “voltage” in the code. To use a different analog input on another Arduino board, update the variable “sct_pin” accordingly.

Working

When taking measurements with the sensor, it is important to only apply ONE of the wires as shown in the below image.

If both wires are put inside the sensor, the values will cancel, resulting in a reading of 0 or an incorrect value on the display.