This power supply was my very first project when I started working on electronics and my adapters were giving me trouble and so I decided to make a bench power supply myself.
This power supply provides 0-9V DC, 12V DC and 24V AC power. YOu can also observe a bulb in top right side and that is because I manufacture voltage regulator circuits and this bulb is for testing out them.
So let's begin with how I made this big box.
Note: I have made this power supply by using old and waste electronic components. You will see various transformers in images and that's because something is wrong with the main transformer. Just follow the steps and you can also make your own power supply.
Step 1: You Will Need
1. 230V - 24V AC, 12V AC and 9V AC transformer
3. 230V - 9V AC transformer
5. 12V AC - DC converter circuit (1N4007's)
6. 2k2 resistors
7. 1 mega Ohm trimpot
10. Wooden cabinet
Step 2: MCB
First of all connect mains wire to MCB and use the output of MCB as input to transformer. This adds the protection and also acts as a switch to whole thing.
Step 3: Getting 24V AC and 12V DC
We are using a 230V - 24V AC, 9V AC and 12V AC transformer to get our required 24V and 12V. I want 24V AC because I use it widely and so I have connected it directly to output via switch.
But for 12V DC, I had an old circuit which was useless and so I decided to use its rectifier to convert 12V AC to 12V DC. Then connected the output of converter to output via switch.
Also, it is easy to convert 12V AC to DC with the help of simple rectifier circuit.
Step 4: Converting 12V AC - 12V DC
This circuit is a rectifier circuit with 1N4007 diodes and this circuit will convert 12V Ac to DC and then our output is ready.
Step 5: Indications for 24V and 12V
We can't connect LED directly with resistor for 24V AC. For 12V DC it is easy to just connect a 2k2 resistor in series.
But for 24V AC, we have two use a diode and series resistor circuit for connecting LED. The reverse diode here protects the LED against the reverse voltage.
Step 6: 0 - 9V Power Supply
The transformer we used also proides 9V AC. So we have to convert 9V AC - 9V DC. For this a simple rectifier circuit and filter circuit would do the job. Then I have used 1M ohm variable resistor to make it 0 - 9V DC adjustable power supply.
Step 7: Cover
I have also made a cover for front side. I have attached a metal plate in bottom and adjusted the piece of wood inside.
Step 8: Job Done
Now, you have made your own bench power supply. However I have made these power supply according to my needs and you should make your power supply according to your powering needs.
Thank you and I hope you like these instructions!