How to Use MEAN WELL Switching Power Supply 12vdc 3A: Examples, Pinouts, and Specs

The MEAN WELL RS-35-12 is a compact and reliable switching power supply designed to convert AC voltage into a stable 12V DC output. With a maximum output current of 3A, this power supply is ideal for powering a wide range of electronic devices and circuits. Its robust design ensures high efficiency, low power consumption, and long-term reliability.

• Powering microcontrollers, sensors, and development boards (e.g., Arduino, Raspberry Pi)
• Driving LED strips, modules, and lighting systems
• Supplying power to industrial control systems and automation equipment
• General-purpose DC power supply for hobbyist and professional projects

The following table outlines the key technical details of the RS-35-12 power supply:

The RS-35-12 features screw terminal connections for input and output. The pin configuration is as follows:

1. Mounting the Power Supply: Secure the RS-35-12 in a well-ventilated area to ensure proper heat dissipation. Avoid placing it near heat-sensitive components.
2. Connecting the Input:
   • Connect the AC live wire to the L terminal.
   • Connect the AC neutral wire to the N terminal.
   • Optionally, connect the earth wire to the FG terminal for safety.
3. Connecting the Output:
   • Connect the +V terminal to the positive input of your load or circuit.
   • Connect the -V terminal to the ground of your load or circuit.
4. Powering On: After verifying all connections, supply AC power to the input terminals. The power supply will output a stable 12V DC.

• Input Voltage: Ensure the input voltage is within the specified range (85-264VAC). Exceeding this range may damage the power supply.
• Load Requirements: Do not exceed the maximum output current of 3A. Overloading may trigger the built-in overcurrent protection or damage the unit.
• Ventilation: Maintain adequate airflow around the power supply to prevent overheating.
• Safety: Always disconnect the power supply from the mains before making any wiring changes.

The RS-35-12 can be used to power an Arduino UNO via its DC barrel jack or VIN pin. Below is an example circuit and Arduino code to blink an LED:

1. Connect the +V terminal of the RS-35-12 to the VIN pin of the Arduino UNO.
2. Connect the -V terminal of the RS-35-12 to the GND pin of the Arduino UNO.
3. Connect an LED and a 220-ohm resistor to pin 13 of the Arduino UNO.

// Simple LED Blink Example
// This code blinks an LED connected to pin 13 of the Arduino UNO.

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
}

1. No Output Voltage:

   • Verify that the input AC voltage is within the specified range.
   • Check all connections to ensure they are secure and correct.
   • Ensure the load does not exceed the maximum output current of 3A.

2. Overheating:

   • Ensure the power supply is installed in a well-ventilated area.
   • Check for any obstructions blocking airflow around the unit.

3. Intermittent Operation:

   • Verify that the input voltage is stable and not fluctuating.
   • Check for loose connections or damaged wires.

4. Output Voltage Too Low:

   • Confirm that the load is not drawing more current than the rated 3A.
   • Inspect the output terminals for proper connections.

Q: Can the RS-35-12 be used outdoors?
A: No, the RS-35-12 is not weatherproof. It should be used in a dry, indoor environment.

Q: Does the RS-35-12 have short-circuit protection?
A: Yes, the RS-35-12 includes built-in short-circuit, overload, and overvoltage protection.

Q: Can I adjust the output voltage?
A: Yes, the RS-35-12 has a small potentiometer for fine-tuning the output voltage within a limited range (±10%).

Q: Is the RS-35-12 suitable for battery charging?
A: While it can be used for basic battery charging, it is not specifically designed for this purpose. Use a dedicated battery charger for optimal performance and safety.