Portable Breadboard With Voltage Regulator for 9V Battery (and Other External Sources)

Introduction: Portable Breadboard With Voltage Regulator for 9V Battery (and Other External Sources)

About: I like to build, scavenge material from junkyards, tear up machinery and stuff.

Hello everyone, and welcome to my Instructable!

Today we will cover how to make a simple voltage regulator to power a prototyping board with 5 Volts, using different voltage input methods and values (8 to 35V).

My little mod uses an L7805CV voltage regulator to give a fixed 5V output to the breadboard.

It is fitted with pin headers, screw terminals and 9V battery contacts, to operate from a variety of power supplies, although its main purpose is to be portable.

The Instructable will be composed of easy mini steps, one per part, so don't be alarmed by looking at the quantity of them!

Step 1: The Parts

The needed parts are easily obtainable by scavenging used electronics, as I did, but they won't cost much if you want to buy them.

- L7805CV voltage regulator. I recommend to attach a heatsink to it, as you might get burned or damage the regulator if you have a high power output.

- a switch

- an indication LED

- a 200~300ohms resistor for the LED, its colours should be: [ RED | any colour | BROWN ] (I know the picture is wrong, sorry)

- 3 headers

- 9V battery contacts

- 24x3 soldering board piece

- a breadboard

- a sheet of plastic onto which we will glue the breadboard and the regulator board

- wires.

The needed tools are a soldering iron and a hot glue gun, which can be replaced with any liquid glue.

To cut the soldering board I use a pair of pliers. Hold it where you want to break it (along a line of holes) and bend it with your hand. It will start cracking, do it along the line to weaken it, then snap it.

Step 2: Solder the Headers

The board piece has 3 lines of holes.
1st line: input voltage
2nd line: ground
3rd line: 5V

Put the headers at one end of the board, and solder them.

They will be useful to pick up or supply voltage using female headers (like computer fans, etc...)

Step 3: Solder the Screw Terminals

Solder the screw terminals.

I soldered them slightly sideways because I wanted to keep everything slender. Just put one pin in the input line, and the other in the GND line, as shown in the pictures. You may add a 3-pins terminal to have access to 5V as well.

Step 4: Solder the 9V Contacts Wires

Solder the wires. Remember the positions, as shown in the picture.

Step 5: Solder the Switch

The switch will turn on and off the voltage regulator, thus it will be soldered along the input line.

Step 6: Solder the L8705CV

By looking at it from the front, the center pin is the GND, the one on the left is the input, and the one on the right is the 5V output.

Solder it facing away from the already placed components.

Step 7: Solder the Resistor

The resistor will be needed to limit the current through the LED.

Solder it along the 5V line.

(The picture shows a 22 ohms resistor, I changed it later to a 270 ohms one)

Step 8: Solder the LED

Solder the LED.

The positive lead (the one with the smaller part inside the cap) goes in the 5V line, next to the resistor end.

The negative lead, the one which has a cut in the plastic cap and has the bigger part in it, goes in the GND line.

Step 9: Solder the Wires

Solder the wires to connect the various leads.

The GND wire is a straight wire that connects ALL the leads on its line. Start with this as it can become difficult to solder with another wire next to it.

Be sure to leave a gap between the leads of the switch, as well as under the resistor!

Step 10: Test It!

Will it work? attach a battery, power it from different points, and see if the LED light up!

If it doesn't, check all the soldering points to see if they are in the right place and conduct as they should.

Step 11: Solder the Breadboard Powering Wires

Now that you know it works, it is time to attach the wires that will bring the power to our breadboard.

Keep the wires long (some centimeters) as we will cut them down to the right length after we glue everything together.

Step 12: Put It Together

Glue the breadboard and the regulator board on the plastic sheet, I used hot glue.

Cut the wires to the exact measure and insert them in the breadboard.

Step 13: Done!

It's done and it's working. Hopefully!

I hope you found my Instructable useful.

Thanks for viewing, have fun with your new portable breadboard!

That's all, folks!

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    4 Discussions


    7 years ago on Introduction

    you need 2 capcitors and a rectifier bridge at least that what I had seen


    Reply 7 years ago on Introduction

    The rectifier bridge is useless, as it is already powered in DC.
    The input capacitor is required to filter disturbs, which are not battery-generated, and that require a long wire from the input filter to be significant.
    The output capacitor is optional, as it improves transient response, not necessary for a prototyping board.


    Reply 7 years ago on Introduction

    I see, so the simpler the better in this case, thanks!