DIY Capacitor

In this Instructable I will be making one of the easiest high voltage capacitors that I know of.....

WARNING High voltage electricity can cause death and serious injury.I do not recommend that anyone work with high voltage power sources unless they know how to do it safely.

Step 1: Getting the materials

You will need:

1.A long screw
2.Some tin foil
3.A 2L bottle
4.some salt and hot water
5.Electrical tape

The first thing you do is get the cap and put a big screw in it.

Comments

[whiskeysausage]

Can you trickle charge a capacitor? For example, from a small solar panel? If I have a 400mf Capacitor, can it take varying trickle charges in and still reach its full potential?

Or, would I have to hook the panel up to a small 6v battery, and funnel the voltage into the capacitor that way? What if the battery only has 100mah, is that relevant?

[hawks88]

Would using copper foil make it better?

[chris1990king]

C= (dielectric constant) x (area / distance)

What Area do you use and what distance?
Is it the diameter of the bottle?

[jabujavi]

How many farads is that?

[monney95]

Why is there no internal foil layer like in a typical leyden jar? I have made one and will test but am not sure if it will work for this fact.

[~KnexBuild~]

The saltwater (a conductor) acts as the internal foil.

[aliampolizzi]

what is the capacity of this leyden jar?
nice project though.

[polishdude]

How do you charge the capacitor up?

[erichahn525]

High Voltages, Televisions work decently, high voltage transformers, or even a van de graph generator. But be very careful, if you build it larger than a masonry jar it can get dangerous and possibly deadly. Do not play around with electricity if you don't know what your doing.

[jakesllama]

you know what im thinking? worlds strongest electromagnet ever! thanks for the compaciter i will try to make it!!

[TyMan210]

 The strongest ever is over 500,000x stronger than the earth's.

[erichahn525]

The strongest ever has been recently created using graphene inside a lab environment measured at about 300 telsas. To put this into relativity, a really strong magnet, one of those rare earth, or neodymium magnets are about .7 teslas. Read up on it here: http://www.rdmag.com/News/2010/07/Materials-Magnetism-Graphene-under-strain-creates-gigantic-pseudo-magn/ so 10 Million at this point!

[liny]

I wouldn't recomend it but you could try. To make the world's strongest, you will need to beat the Navy's Gaussian guns (railgun and coil guns) with capacitors that can vaporize you. After that, you will need to beat the actual strongest (i think) electromagnet that can (more or less) defy gravity (it makes apples and stuff float, even water, just like an anti-gravity space). As a side note, the electromagnet is bigger than a house.

[hurtzmyhead]

worlds strongest? your going to need a lot of 2lt bottles!!!!!!

[ARJOON]

still best to buy one 10X smaller 

[teslacoilguitaramp,helpmeplz]

when i saw this i thought. that looks unreliable and overly dangerous, and sketchy, i give a forewarning i would not do this, and i am tring to build a tesla coil. so i am being nice and revving a friendly warning.

[conb3]

If you add lemon juice to the water will it make it more conductive ?

[Crtek]

could anyone tell me if the screw should be touching the water inside the bottle or not. i can't seem to find this info anywhere

oh and how would one connect multiple capacitors like this in series?

[nutsandbolts_64]

It should be. As for connecting them in series, connect the positive to the negative, then the positive of that capacitor to the negative of another etc. In short, foil to nail, foil to nail. As long as you don't connect the same capacitor to each other twice. By the way, why connect them in series? One is already powerful. People would usually connect them in parallel, but of course, that depends entirely on the use. What are you planning to do with them anyway? Just so that I can satisfy your questions.

[Crtek]

i need them for a tesla coil
so would that mean i need to connect them in series or in parallel?

[bsomerville]

series, for a tesla coil you want as high a voltage as possible (to prevent over-voltage) and as little capacitance as you can (to keep the frequency of discharges through the spark gap high) unless your not using a spark gap coil, in which case i have no idea.

[nutsandbolts_64]

A Tesla Coil? Sorry, I don't have experience building tesla coils. There are instructables floating around that could have people that can answer your question. Or you can post the question as a question in the first place.

[techno guy]

Is the bright spark in the last picture done with static electricity or with high voltage ac or dc? I made my own capacitor, its smaller but its awesome if you connect it with high voltage ac (500+ volts) like from a flyback it makes some awesone sparks and you could sometimes make small corona discharges.

[7654321]

you cant charge a capacitor with ac, can you?

[Void Schism]

Because it is alternating, it will charge in one direction, then when the current reverses it will be discharged.
If you want to use an AC source you need to rectify it. The easiest way to do that is to use a (high-voltage) diode to only allow current to flow in one direction, thus preventing discharge.

[techno guy]

To make a capacitor bank with these, what would be better, hook them up in parallel, or in series?

[7654321]

sorry didnt read well, what would you be using this for? if you want to increase the voltage, than do it in series, if you want to make it last longer do in parallel

[7654321]

With capacitors, in series reduces capacitance using formula (c1*c2)/(c1+c2), in parallel increases capacitance, so in parallel would be better.

[fostersfriend]

Dude this just doesn't work i substituted the expensive table salt for driveway salt replaced the plastic bottle with a glass bottle I just happened to have after I did it all I was left with a worthless bottle of saltwater I tried charging it with a 9 volt then a dc power supply then a high voltage low amperage grill igniter and nothing no spark no reading on the meter nothing
What did I do wrong they make capacitors with glass layers?

[Crtek]

by the way...i've seen loads of capacitors made from a can (Al) on the inside and Al foil on the outside
are those better in anyway or can i just make the water kind?
thanks for your answers

[rocket_man]

Alright stupid question but about how much voltage could one of these charge up to

[Brian Wall]

wats the srew for?

[mikmkt93]

its the contact. if u touche the the scw to the aluminum foil with a wire it sparks

[micronxd]

nice design! I never thought of using a bottle! I've only made a simple one out of paper... nothing like this!

[flubs]

 how do you make one outta paper

[jj.inc]

 a layer of foil, a layer of paper, a layer of foil.  

[beehard44]

nice and simple...

[nutsandbolts_64]

nice and simple *layers 20 of those and connects them together* SHI---

[Jimmy Proton]

i made one with paper once but it diddnt work

[nutsandbolts_64]

aww... I guess cardboard would do better :D