How to Use AC to 12V DC 20A: Examples, Pinouts, and Specs

The WEIYU S120-12 240W is a high-performance AC to DC power supply converter designed to transform alternating current (AC) voltage into a stable 12 volts direct current (DC) output. With a maximum current capacity of 20 amps, this power supply is ideal for powering high-current DC devices such as LED strips, motors, industrial equipment, and other electronics requiring a reliable 12V DC source.

• LED lighting systems (e.g., LED strips, panels, and signage)
• Industrial automation and control systems
• Security camera systems
• DIY electronics projects
• Powering DC motors and actuators
• Charging 12V batteries (with proper charging circuitry)

The following table outlines the key technical details of the WEIYU S120-12 240W power supply:

The WEIYU S120-12 240W power supply has the following input and output terminals:

Note: Ensure the AC input voltage selector switch is set correctly (110V or 220V) before powering the device.

1. Input Connection:

   • Connect the live (L) and neutral (N) wires of the AC mains supply to the respective input terminals.
   • Connect the ground (GND) terminal to the earth wire for safety.

2. Output Connection:

   • Connect the V+ terminals to the positive input of your DC load.
   • Connect the V- terminals to the negative input (ground) of your DC load.
   • For high-current applications, use both V+ and V- terminals in parallel to distribute the load evenly.

3. Voltage Adjustment (Optional):

   • Use the small potentiometer near the output terminals to fine-tune the output voltage (±10%).

4. Power On:

   • Ensure all connections are secure and insulated.
   • Switch on the AC mains supply to power the device.

• Input Voltage Selection: Always set the input voltage selector switch to match your AC mains supply (110V or 220V). Incorrect settings can damage the power supply.
• Load Capacity: Do not exceed the maximum output current of 20A or the total power rating of 240W.
• Ventilation: Ensure adequate airflow around the power supply to prevent overheating.
• Safety Precautions: Avoid touching live terminals during operation. Disconnect the power supply before making any adjustments or connections.

The WEIYU S120-12 240W can be used to power an Arduino UNO and other peripherals. Below is an example circuit and code:

1. Connect the V+ terminal of the power supply to the VIN pin of the Arduino UNO.
2. Connect the V- terminal of the power supply to the GND pin of the Arduino UNO.
3. Ensure the output voltage is set to 12V DC.

// Example code to blink an LED connected to pin 13 of the Arduino UNO
// Ensure the Arduino is powered by the WEIYU S120-12 240W power supply

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

Note: The VIN pin on the Arduino UNO requires a voltage between 7V and 12V. The 12V output from the power supply is within this range.

1. No Output Voltage:

   • Check if the AC mains supply is connected and switched on.
   • Verify the input voltage selector switch is set correctly (110V or 220V).
   • Inspect the fuse inside the power supply for damage and replace if necessary.

2. Overheating:

   • Ensure the power supply is not overloaded (current > 20A or power > 240W).
   • Check for proper ventilation and remove any obstructions around the device.

3. Voltage Fluctuations:

   • Verify the load is within the rated capacity.
   • Adjust the output voltage using the potentiometer if necessary.

4. Short Circuit Protection Triggered:

   • Disconnect the load and inspect for short circuits.
   • After resolving the issue, reconnect the load and power on the device.

Q: Can I use this power supply to charge a 12V battery?
A: Yes, but you must use a proper charging circuit to regulate the charging current and prevent overcharging.

Q: Is the power supply waterproof?
A: No, the WEIYU S120-12 240W is not waterproof. Use it in a dry and well-ventilated environment.

Q: Can I connect multiple devices to the power supply?
A: Yes, as long as the total current draw does not exceed 20A and the total power does not exceed 240W.

Q: How do I replace the fuse?
A: Open the power supply casing (if safe to do so) and replace the fuse with one of the same rating. Ensure the device is disconnected from the mains supply before attempting this.

By following this documentation, you can safely and effectively use the WEIYU S120-12 240W power supply in your projects.