Need a strong 12V DC supply for our electronics projects? then a stable and powerful DC supply is the heart of any electronics project.
Also, this Transformer Based 12V DC 3A Power Supply Circuit delivers clean and reliable power and it converts AC mains into smooth DC power and it provides high current with low noise output.
Furthermore, it is simple to build and uses easily available components and is perfect for hobbyists, students and DIY electronics lovers.
Circuit Working:

Parts List:
| Components | Values | Quantity |
|---|---|---|
| Resistor | 1.2k 1/4 watt | 1 |
| Capacitors | Electrolytic 2200uF 25V | 4 |
| Ceramic 0.1uF | 1 | |
| Bridge Rectifier 6A 100V | 1 | |
| LED any 5mm | 1 | |
| Step-Down Transformer 12V, 3A Secondary, 220V AC Primary | 1 | |
| ON/OFF Switch SPST | 1 | |
| Fuse 1A | 1 |
In this article transformer reduces high AC voltage to 12V AC and then bridge rectifier changes AC into pulsating DC.
Capacitors C1 to C4 smooth the DC supply, and capacitor C5 removes small high-frequency noise; then the LED turns ON when DC power is available, and the circuit takes the DC output from the positive terminal of the capacitor and the ground terminal.
How to Build:
To build a Transformer Based 12V DC 3A Power Supply Circuit following are the steps we need to follow:
- First, gather all the parts as shown in circuit diagram.
- Next, transformer primary pins connect to AC mains via switch and fuse and transformer secondary pins connect to bridge rectifier AC pins.
- Then bridge rectifier positive pin connects to capacitor positive rails and bridge rectifier negative pin connects to ground line.
- Also, all capacitor positive pins connect together at the output and all capacitor negative pins connect to ground.
- After that, LED anode connects to output through resistor R1 and LED cathode connects to ground.
Conclusion:
To conclude, this Transformer Based 12V DC 3A Power Supply Circuit is simple and effective, it uses easily available components and provides high current DC output.
Additionally, it is best for non-sensitive electronics and by adding a regulator we can improve voltage stability.