If you're looking for an efficient way to control a 12V fan using either AC or DC input, this DIY project is perfect for you! Using a 12V 3000mA transformer, diodes, and a few essential components, we’ll guide you step-by-step to build a 12V AC/DC Fan Controller Module — ideal for battery packs, solar systems, or power backup setups.

⚙️ What is a 12V AC/DC Fan Controller?

1. A 12V AC/DC fan controller allows you to operate a 12V fan directly from an AC supply or a 12V battery. This is especially useful for:
2. UPS systems
3. Battery-powered cooling
4. Solar energy setups
5. Emergency ventilation systems

Components List:

1. 12V 3000mA Transformer – 1 piece
2. 1N5408 Diode – 2 pieces
3. 1N5822 Diode – 3 pieces
4. 1N5819 Diode – 1 piece
5. 2200µF Electrolytic Capacitor – 1 piece
6. 220µF Electrolytic Capacitor – 1 piece
7. 10kΩ Resistor – 2 pieces
8. 1kΩ Resistor – 2 pieces
9. LM2596T-ADJ Voltage Regulator – 1 piece
10. AUIP0540N N-Channel MOSFET – 1 piece
11. 880µH Inductor – 1 piece
12. 5mm Red LED – 1 piece
13. SPST Switch – 1 piece
14. 3-Pin Connector – 1 piece
15. 2-Pin Connector – 2 pieces
16. PCB Board – 1 piece
17. Heat Sink for LM2596T – 1 piece (optional but recommended)
18. Fuse or Polyfuse – 1 piece (optional for protection)

🔌 How the Circuit Works

Step-by-Step Breakdown:

AC Input to DC Conversion:

A 12V 3000mA transformer steps down 220V AC to 12V AC.

D1 & D2 (1N5408) act as a full-wave rectifier.

The 2200µF capacitor (C1) smooths the rectified output.

Voltage Regulation:

The LM2596T-ADJ buck converter regulates the DC voltage and provides a stable output to the fan and battery.

Battery Integration:

The 1N5819 diode ensures the battery does not feed back into the circuit when AC is available.

When AC is off, the MOSFET (Q2) and D5/D6 (1N5822) manage switching to the battery.

Fan Load Control:

The MOSFET AUIP0540N acts as a switch for the fan.

A manual switch (SW) can be used to toggle fan operation.

Status Indication:

LED1 shows power availability.

💡 Features

✅ Automatic switching between AC and battery

✅ Works with any 12V fan or load

✅ LED indicator for power status

✅ MOSFET-based efficient fan control

✅ Protection from reverse current and voltage spikes

🛠️ Assembly Tips

1. Use a heat sink on the LM2596T for better performance.
2. Ensure correct diode orientation to avoid reverse polarity.
3. Test the board with a multimeter before connecting the fan.
4. Use a fuse or polyfuse for added protection.

Video Reference:

🧠 Final Thoughts

This simple but powerful circuit is a great addition to your DIY toolkit. Whether you're a hobbyist or building a reliable fan controller for a solar setup, this module is cost-effective and easy to assemble.