How to Use Ky-22: Examples, Pinouts, and Specs

The Ky-22 is a relay module designed to control high-power loads using low-power signals. Manufactured under part ID "Uno," this component is widely used in automation, control systems, and other electronic applications requiring electrical isolation between control and load circuits. Its compact design and reliable switching capabilities make it a popular choice for hobbyists and professionals alike.

• Home automation systems
• Industrial control systems
• Motor control circuits
• Smart appliances
• Robotics and IoT projects

The Ky-22 relay module is designed to operate efficiently in a variety of electronic circuits. Below are its key technical details:

• Operating Voltage: 5V DC
• Trigger Voltage: 3.3V to 5V DC
• Maximum Load Voltage: 250V AC or 30V DC
• Maximum Load Current: 10A
• Relay Type: SPDT (Single Pole Double Throw)
• Isolation: Optocoupler-based electrical isolation
• Dimensions: 32mm x 14mm x 18mm (approx.)
• Weight: ~10g

The Ky-22 relay module typically has 5 pins for input and output connections. Below is the pinout description:

The Ky-22 relay module is straightforward to use in electronic circuits. Follow the steps below to integrate it into your project:

1. Power the Relay Module:

   • Connect the VCC pin to a 5V DC power supply.
   • Connect the GND pin to the ground of the power supply or control circuit.

2. Control the Relay:

   • Connect the IN pin to a digital output pin of a microcontroller (e.g., Arduino UNO).
   • Send a HIGH signal (3.3V to 5V) to the IN pin to activate the relay and switch the load.

3. Connect the Load:

   • Identify whether you want the load to be connected to the NO (Normally Open) or NC (Normally Closed) terminal.
   • Connect the load to the appropriate terminal (NO or NC) and the COM terminal.

4. Test the Circuit:

   • Power the circuit and send control signals to the IN pin to toggle the relay state.

• Ensure the load voltage and current do not exceed the relay's maximum ratings (250V AC/30V DC, 10A).
• Use proper insulation and safety precautions when working with high-voltage loads.
• Avoid rapid switching of the relay to prevent wear and tear on the mechanical contacts.
• Use a flyback diode across the relay coil to protect the circuit from voltage spikes.

Below is an example of how to control the Ky-22 relay module using an Arduino UNO:

// Example code to control the Ky-22 relay module with Arduino UNO

// Define the pin connected to the relay module's IN pin
const int relayPin = 7;

void setup() {
  // Set the relay pin as an output
  pinMode(relayPin, OUTPUT);

  // Initialize the relay in the OFF state
  digitalWrite(relayPin, LOW);
}

void loop() {
  // Turn the relay ON
  digitalWrite(relayPin, HIGH);
  delay(1000); // Keep the relay ON for 1 second

  // Turn the relay OFF
  digitalWrite(relayPin, LOW);
  delay(1000); // Keep the relay OFF for 1 second
}

1. Relay Not Switching:

   • Cause: Insufficient voltage or current to the IN pin.
   • Solution: Ensure the control signal is between 3.3V and 5V DC.

2. Load Not Powering On:

   • Cause: Incorrect wiring of the load to the relay terminals.
   • Solution: Verify the load is connected to the correct terminals (NO or NC) and COM.

3. Relay Clicking Rapidly:

   • Cause: Unstable control signal or noise in the circuit.
   • Solution: Use a pull-down resistor on the IN pin to stabilize the signal.

4. Overheating Relay:

   • Cause: Load exceeds the relay's maximum current rating.
   • Solution: Ensure the load current is within the 10A limit.

• Q: Can the Ky-22 relay module be used with a 3.3V microcontroller?
  A: Yes, the IN pin can accept control signals as low as 3.3V DC.

• Q: Is the Ky-22 relay module suitable for switching DC loads?
  A: Yes, it can switch DC loads up to 30V and 10A.

• Q: Does the Ky-22 provide electrical isolation?
  A: Yes, it uses an optocoupler for electrical isolation between the control and load circuits.

• Q: Can I use the Ky-22 to control an AC motor?
  A: Yes, as long as the motor's voltage and current are within the relay's maximum ratings (250V AC, 10A).