How to Use SCT-013 Current Sensor: Examples, Pinouts, and Specs

The SCT-013 is a non-invasive current sensor designed to measure alternating current (AC) by clamping around a conductor. Manufactured by Arduino under the part ID Sen0211 with SCT-013, this sensor outputs a voltage proportional to the current flowing through the conductor. It is widely used in energy monitoring systems, home automation, and industrial applications for tracking power consumption and optimizing energy usage.

• Energy monitoring in residential and industrial environments
• Smart home automation systems
• Power consumption analysis for appliances
• Renewable energy systems (e.g., solar or wind energy monitoring)
• Overcurrent detection in electrical systems

• Model: SCT-013
• Manufacturer Part ID: Sen0211
• Input Current Range: 0–100 A AC (varies by model variant)
• Output Signal: Voltage (proportional to current)
• Accuracy: ±1% (typical)
• Output Connector: 3.5 mm audio jack
• Core Material: Ferrite
• Operating Temperature: -25°C to +70°C
• Dielectric Strength: 6000 V AC (1 minute)
• Cable Length: 1 meter (standard)

The SCT-013 sensor uses a 3.5 mm audio jack for its output. The pinout is as follows:

1. Connect the Sensor:

   • Clamp the SCT-013 sensor around the live or neutral wire of the AC circuit you want to monitor. Ensure the wire is insulated and the clamp is securely closed.
   • Plug the 3.5 mm audio jack into the input of your circuit or microcontroller interface.

2. Voltage Divider Circuit:

   • The SCT-013 outputs an AC voltage proportional to the current. To interface with a microcontroller (e.g., Arduino UNO), you need a voltage divider circuit to bias the signal to the mid-point of the ADC range (typically 2.5 V for a 5 V system).
   • Use two resistors of equal value (e.g., 10 kΩ) to create the voltage divider.

3. Connect to Arduino UNO:

   • Connect the signal output (tip) to an analog input pin (e.g., A0) on the Arduino.
   • Connect the ground (ring) to the Arduino's GND pin.

4. Calibration:

   • The output voltage of the SCT-013 is proportional to the current, but calibration is required to convert the ADC readings into actual current values. Use a known load to determine the calibration constant.

// Example code for using the SCT-013 current sensor with Arduino UNO
// This code reads the sensor output and calculates the RMS current.

const int sensorPin = A0; // Analog pin connected to SCT-013 signal output
const float calibrationFactor = 100.0; // Adjust based on your sensor model
const int numSamples = 1000; // Number of samples for RMS calculation

void setup() {
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  float sum = 0; // Variable to store the sum of squared readings

  // Take multiple samples to calculate RMS
  for (int i = 0; i < numSamples; i++) {
    int rawValue = analogRead(sensorPin); // Read the analog value
    float voltage = (rawValue / 1023.0) * 5.0; // Convert to voltage
    float current = (voltage - 2.5) * calibrationFactor; 
    // Subtract 2.5 to remove bias, then scale by calibration factor
    sum += current * current; // Square the current and add to sum
    delay(1); // Small delay between samples
  }

  float rmsCurrent = sqrt(sum / numSamples); // Calculate RMS current
  Serial.print("RMS Current: ");
  Serial.print(rmsCurrent);
  Serial.println(" A"); // Print current in amperes

  delay(1000); // Wait 1 second before next reading
}

• Safety: Ensure the conductor being measured is insulated and the sensor is clamped securely. Do not use the sensor on bare wires.
• Calibration: The calibration factor depends on the specific SCT-013 model and the burden resistor used. Refer to the datasheet for precise values.
• Noise Reduction: Use shielded cables and proper grounding to minimize noise in the output signal.
• Burden Resistor: Some SCT-013 models include an internal burden resistor, while others require an external one. Verify your model's configuration before use.

1. No Output Signal:

   • Ensure the sensor is clamped around a live or neutral wire carrying current.
   • Verify the 3.5 mm jack is securely connected to the circuit.

2. Inaccurate Readings:

   • Check the calibration factor and ensure it matches your sensor model.
   • Verify the burden resistor value and connections.

3. High Noise in Output:

   • Use shielded cables and ensure proper grounding.
   • Avoid running the sensor cable parallel to high-voltage lines.

4. Arduino ADC Saturation:

   • Ensure the voltage divider circuit biases the signal correctly within the ADC range.
   • Check for excessive current that may cause the sensor to output a voltage beyond the ADC range.

Q1: Can the SCT-013 measure DC current?
A1: No, the SCT-013 is designed for AC current measurement only. It cannot measure DC current.

Q2: What is the maximum current the SCT-013 can measure?
A2: The maximum current depends on the specific model variant. Common models measure up to 30 A, 50 A, or 100 A.

Q3: Can I use the SCT-013 with a Raspberry Pi?
A3: Yes, but since the Raspberry Pi lacks an analog-to-digital converter (ADC), you will need an external ADC module (e.g., MCP3008) to interface the SCT-013.

Q4: How do I know if my SCT-013 has an internal burden resistor?
A4: Check the model number printed on the sensor or refer to the datasheet. Models with an internal burden resistor typically have a voltage output specification (e.g., 1 V or 0.333 V).

By following this documentation, you can effectively integrate the SCT-013 current sensor into your projects for accurate and reliable AC current measurement.