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## Introduction: 5V Breadboard Mini PSU

Micro PSU to power a breadboard with 5 volts.
Connect to 9V battery, 12V or any other DC powersource from 8 to 18 volts.

## Step 1: Components

To build this you need:

• Some electronics skills. Soldering, knowing how to follow a circuit diagram etc..
• 1 voltage regulator LM 7805
• 1 10uF capacitor
• 1 1000uF capacitor (you can use any big electrolyt capacitor here, doesn't have to be exactly 1000uF)
• 1 100nF capacitor
• 1 LED for power on indication
• 1 resistor to to take the voltage down from 5V to whatever your LED runs at
• 1 screw terminal for the input voltage
• 1 switch for input voltage on/off
• 1 perfboard, the type with copper eyes, not stripes
• 1 2-pin connector to plug the unit into the breadboard

Resistor calculation

R = ohm of resistor
V = voltage for the LED (You can find this in the datasheet for your LED)
I = current for the LED (can also be found in the datasheet)

R = (5-V) / I
Then round up to the nearest resistor value you can find.

## Step 2: Minimize

Place all the components on a perfboard to see how tiny you can make it.
I won't give any detailed instructions here, as the size and layout of the parts you use may vary from mine.

Put the components in as tight as you can, while verifying that you can in fact complete the circuit on the underside of the board without adding any wires.

When you've found your minimum size, cut out the piece you need.

## Step 3: Solder

when you have figured out a way to squeeze your components together, it's time to solder.

Check the pictures to see how I did it.

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## Questions

Anyone know what the ceramic cap is for? I don't have 100 pF so can I use a 500pF or 1000pF cap? Thanks

The 100 pF capacitor reduces noise. It will work without the capacitors. But to be on the safe side, and provide a stable power source, we add capacitors. The 500pF will work just fine :)

will the 1uF work?

Hi, it that a 100pF capacitor or a 100nF capacitor? In the photo you show 100nF.
Thanks!

oh sorry I didn't see it at first.

I know how all this works but can you post a schematic? I have a large breadboard and I can just plug all the stuff in a little corner somewhere

how did you solder like that? whenever i do it, the solder all clumps together onto one pad.

Usually when you bridge solder two joints, you ball up both pins, then get a little solder on the iron and start applying between the points. If there is enough solder on the iron or the 2 pins or all 3, then the bridge will automatically join together. But do it quickly because you do not want to burn the electronics. If it does not work the first time, add a little more solder until they join.

ok, well i figured it out anyway. thanks. i like this way of soldering, even though it uses a lot of solder.

Why don't u use staples?