## Introduction: Recycled Milli-Volt Power Supply

Hello, I have here Milli Volt Power Supply. It is recycled, variable and battery powered. It is made of enclosures and components found from scrap and junkyard. One Day my dad told me to make a Milli Volt Power Supply. Actually he wanted 20mV. I asked him the use of it and he answered that he wanted to use that as pulse for magnetic reed switches. Then I gathered the components and made it functional.

The circuit contains a 7805 Voltage Regulator IC, some resistors and potentiometer to adjust the voltage. It can give up to 45 Milli volts. The circuit is easy to understand and simple to make.

I am sure you will find it interesting!!!!

## Step 1: Gather Materials

The components follows are found from junkyard:

1. Resistor Box(You only need 1k, 10k and 100 ohms Resistors from it)

2. Regulator Enclosures

3. Toggle Switch

4. Piece of Cardboard

Things you may not find from scrap:

1. 10k Potentiometer(DIGIKEY)

2. 3 pin connector(DIGIKEY)

3. 7805 Voltage Regulator IC(DIGIKEY)

4. 9V Battery(DIGIKEY)

5. Battery Snapper(DIGIKEY)

6. Multi meter(DIGIKEY)

Not going to junk yard? Here are the DIGIKEY Links of components:

1. 1k Resistor(DIGIKEY)

2. 10k Resistor(DIGIKEY)

3. 100 ohms Resistor(DIGIKEY)

4. Toggle Switch(DIGIKEY)

## Step 2: The Circuit

The circuit contains 7805 Voltage Regulator IC, Some Resistors and a potentiometer. 7805 Voltage Regulator IC converts 9V to 5V first of all. Then comes 1k Resistor in series. A potentiometer is attached to adjust the voltage.

## Step 3: Circuit on Breadboard

To make circuit on breadboard, first of all mount 7805 Voltage Regulator Ic and from its 2nd pin take out negative terminal and from its 3rd pin attach 1k Resistor.

## Step 4: Still Making

Now, take out positive terminal and negative terminal for the output and also attach 100 ohm Resistor.

## Step 5: Potentiometer

Now, place a potentiometer with the help of a 3 pin connector and also connect the battery.

## Step 6: Testing

Check the output voltage with the help of multi meter and also use potentiometer to get the desired voltage.

## Step 7: Circuit on PCB

Assemble the components on PCB as per the circuit diagram. Use a 3 pin Connector for Potentiometer.

## Step 8: Hole

Make hole on enclosure at place where you want to place switch. You know how i did it? With useless old solder tip. Regulator Enclosures have hole for variable Resistor. So no need to make one more.

## Step 9: Switch

Cut the red wire from the battery snapper to insert switch. Insert the switch by soldering cut wires to switch.

## Step 10: Put in the Box

Put the PCB in the Box. Also fix the switch in the hole.

## Step 11: Big Holes Are Problem

I have a pretty big hole for potentiometer. So, I used piece of cardboard, made a hole and fixed potentiometer in it and stuck the cardboard to enclosure.

## Step 12: Attach Potentiometer

Attach the potentiometer to 3 pin connector and close the box by screwing it!

## Step 13: Power Supply Ready

Now, You Power Supply is Ready.

I hope you enjoyed it.

Have a Great Day.

Thanks for stopping By!!!!!

Participated in the
Before and After Contest 2017

Participated in the
Power Supply Contest

Participated in the
Invention Challenge 2017