Instructables
Picture of How to Make a Voltage Inverter

Hello There!
Now, heres my first Instructable and Ill show you, how to make a small Voltage Inverter (I mean, getting a NEGATIVE Voltage out of a POSITIVE) on you Bredboard.

Some Amplifying circuits need negative voltage to work good. This circuit schould deliver enough current to power a small OpAmp or so.

Step 1: Part List

Picture of Part List

Now, youll' need some Parts you can easily from you local electronics store.

-1x Bredboard (To mount everything on, you could even use a small Stripboard to solder everthing on)
-1x NE555 (Tiny Timer Chip, the Heart of the Circuit)
-Capacitors: -1x 25 Volt, 47 - 220µF (For Testing, Get more than One ;))
                       -1x 16 Volt (or Higher), 0.1 - 1µF (Same Here)
                       -1x 25 Volt (or Higher) 470 - 2200µF
Resistors: -3x 1.5kOhm ( 1k will work,too)
                    -1x 100kOhm (With this one you could Mess around, so you could use anything between 1k - 820k, Its up to you!)
-2x 1N4001 Diode (You can use nearly every kind of Diode, but prevent using Zener Diodes. They wont work.)
- 9V Battery or other Powersupply (If youre' using a Wallwart, make sure you put some Ripple-filter caps on the powerlines)
Finally, Some LEDs with the color of your choice.2 - 3 or so.
 
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It was easy and I made it for my school project. I also got a first price for this. Thank you

cdousley4 years ago
cool but what exactly is negative and positive voltage and how are they both used all i could find looking around google was about nothing
Lenny24 (author)  cdousley4 years ago
Thanks for Your Comment! Voltage is an "Offset" to 0V.(What ill write now is PHYSICAL and not Chemical.Normaly only electrons flow, but dont make yourself crazy with this.) If you hook up an 9V Battery to an LED (With resistor), the protons(positive charge) flow from the positive side of you Battery to the negative side, because the negative side is has much more negative charge because of the electrons are charged negative.You may know this from two magnets, the S and N pole attract each other. Its the same here. Now, negative voltage means, there are even less protons and more Electrons on this side, which means, the protons flow from the 0V to V-.
Help.JPG
Its been proven that Electrons flow from negative to positive because there are more electrons at the negative end and everything flows from high to low. So doesn't that make everything negative voltage anyhow? So wouldn't this circuit just be reducing the voltage then switching pins so that the voltmeter reads negative? You can make a voltmeter read negative by turning the leads around...
The direction of flow from positive to negative is not for electrons, its for holes, which fill in the electron spots.

You can view it as electrons move from one side to the other
or holes moving in the opposite direction

but not both.
That sounds a tad sketchy to me, but electrons in general are sketchy. Acting as a wave in some instances and acting as waves in others. And I guess it really doesn't what what you view going in either direction when making a circuit, just as long as you keep everything constant. But for proper understanding you are correct, but I have never heard the hole theory before...
Lenny24 (author)  Wesley6664 years ago
Yeah, I know that only electrons flow, but on the diode symbol, it looks like positive charge flows. Well, if you take a look on the last page youll see, the negative lead of the Multimeter is connected to GND and the positive to our V- out.
Dr KAZ Lenny244 years ago
Interesting theory - protons flowing....

No, voltage is a potential difference (as you correctly stated) caused by work done on a certain amount of charge (i.e. Joule/Coulomb = Volt). This charge is indeed electrons flowing, although, by agreement all current is assumed to be due to due to the motion of positive charges. In real life though, it is the electrons that are the charge carriers. They have a drift velocity, which is, surprizingly, very small (less than a millimetre per second) and is not to be confused with the speed at which the elecric field causing their drift motion travels along a conductor. This is close to the speed of light and current therefore starts to flow almost simultaneously at all points in a circuit.

There, now I've gone all crazy, and that after your warning!

Nice instructable.

Dr. KAZ
I understand now! THANK YOU
you said Bredboard
osgeld4 years ago
I just posted this on the arduino forum to drive LCD contrast, course its not my idea, and I would have never thought of it, but durn if you were a couple days earlier it would have saved me a boatload of googling