How to Use 12v power supply: Examples, Pinouts, and Specs

A 12V power supply is an electronic device that converts input power into a stable 12-volt direct current (DC) output. It is widely used in various applications such as powering electronic circuits, computer peripherals, LED lighting systems, and other devices that require a consistent 12V DC power source.

• Powering 12V DC motors
• LED strip lighting
• CCTV camera systems
• Automotive electronics
• Hobbyist electronics projects, including use with Arduino and Raspberry Pi

• Input Voltage: 100-240V AC (50/60Hz)
• Output Voltage: 12V DC
• Output Current: Varies by model (e.g., 1A, 2A, 5A)
• Power Ratings: Varies by model (e.g., 12W, 24W, 60W)
• Efficiency: >80% typically
• Operating Temperature: -10°C to +60°C
• Protection: Overvoltage, Overcurrent, Short Circuit, Overheat

1. Connecting AC Input:

   • Ensure the power supply is unplugged before wiring.
   • Connect the live (L) and neutral (N) wires to the AC input pins.
   • Attach the ground wire to the ground pin if available.

2. Connecting DC Output:

   • Connect the positive terminal of your device to the +12V DC output pin.
   • Connect the ground terminal of your device to the DC output ground pin.

• Always verify the current and power ratings of your device to ensure the power supply can handle the load.
• Use a fuse or circuit breaker on the AC input for additional safety.
• Ensure proper ventilation around the power supply to prevent overheating.
• Do not exceed the rated output current of the power supply to avoid damage.

• Power supply overheats: Ensure adequate ventilation and that the load does not exceed the power supply's ratings.
• No output voltage: Check AC input connections and verify that the power supply is receiving power.
• Voltage drop under load: Ensure that the power supply's current rating is sufficient for the load.

• If the power supply is not turning on, check the AC input connections and the fuse.
• For voltage drops, consider using a power supply with a higher current rating or reduce the load.
• If the power supply overheats, remove any obstructions to airflow and consider adding additional cooling.

• Q: Can I use this power supply with an Arduino UNO?

  • A: Yes, but ensure you regulate the voltage down to 5V using a voltage regulator or a buck converter.

• Q: What should I do if the power supply makes noise?

  • A: Some noise can be normal, but excessive noise may indicate an overload or a failing component. Reduce the load and check the power supply's health.

// Example code to demonstrate how to power an Arduino UNO with a 12V power supply
// through the VIN pin. The Arduino UNO has an onboard voltage regulator that can
// handle input voltages from 7V to 12V.

void setup() {
  // Initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  // Turn the LED on (HIGH is the voltage level)
  digitalWrite(LED_BUILTIN, HIGH);
  // Wait for a second
  delay(1000);
  // Turn the LED off by making the voltage LOW
  digitalWrite(LED_BUILTIN, LOW);
  // Wait for a second
  delay(1000);
}

// Note: When using a 12V power supply, connect the positive terminal to the
// Arduino's VIN pin and the ground to one of the Arduino's GND pins.

Remember to keep the power supply's current rating in mind when connecting additional components to the Arduino to prevent overloading the power supply.