# Arduino Power Supply Shield With 3.3v, 5v and 12v Output Options (Part-1)

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Hello guys! I am back with another Instructable.

When developing electronic projects, the power supply is one of the most important parts of the whole project and there is always a need for multiple output voltage power supply. This is because different sensors need different input voltage and current to run efficiently. So today we will be designing a Multipurpose Power Supply. The Power Supply will be an Arduino UNO Power Supply Shield which will output multiple voltage ranges such as 3.3V, 5V, and 12V. The Shield will be a typical Arduino UNO shield with all pins of Arduino UNO can be used along with extra pins for 3.3V, 5V, 12V and GND.

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## Step 1: Required Hardware

The following components have been used:

1. LM317 – 1 Unit

2. LM7805 – 1 Unit

3. LED – 1 Unit

4. 12V DC Barrel Jack – Unit

5. 220Ω Resistor – 1 Unit

6. 560Ω Resistor – 2 Units

7. 1uF Capacitor – 2 Units

8. 0.1uF Capacitor – 1 Unit

9. Burg Pins(20 mm) – 52 Units

## Step 2: Circuit Schematic & Working

The circuit diagram and schematic for Arduino Power Supply Shield are pretty simple and don’t contain much component placement. We will be using 12V DC Barrel Jack for main voltage input for the whole Arduino UNO Shield. The LM7805 will convert 12V to 5V output, similarly, the LM317 will convert 12V to 3.3V output. LM317 is a popular Voltage regulator IC can be used to build variable voltage regulator circuit.

To convert the 12V to 3.3V we are using 330Ω and 560Ω as voltage divider circuit. It is important to place an output capacitor between the output of LM7805 and Ground. Similarly between the LM317 and Ground. Keep in mind that all grounds should be common and the required track width should be chosen depending upon the current flowing through the circuit.

## Step 3: PCB Design

After making the circuit ready, it’s the time to go ahead with designing our PCB using the PCB design software. As stated earlier I am using Eagle PCB Designer, so we just need to convert the schematic to a PCB Board. When you convert the schematic into the board, you also need to place the components in the places according to the design. After converting the schematic to the board, my PCB looked like the image given above.

## Step 4: Parameter Consideration for PCB Design

1. Trace width thickness is minimum 8 mil.

2. The gap between plane copper and copper trace is a minimum of 8 mil.

3. The gap between trace to trace is a minimum of 8 mil.

4. Minimum drill size is 0.4 mm

5. All the tracks which have current path need thicker traces

We can draw the PCB Schematic with any software as per your convenience. Here I have my own design and Gerber file.

After you generate the Gerber file you can send it to the manufacturer. As you all know, who have read my previous Instructables, I prefer LIONCIRCUITS.

They are an online PCB manufacturer. Their platform is fully automated, you have to upload the Gerber files and the quotation can be seen instantly. They have low-cost prototyping service which is very helpful in these kinds of projects. Try them. Highly Recommended.

Part-2 of this instructable will be released soon. Till then stay tuned.

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