Hi, I want to make my own high voltage capacitor
But what is a capacitor? It is basically made by any two electric
Conductors placed close to each other with some electrical isolator between them. Like two wires
running parallel to each other or two lovers separated by glass.
I Love you, too
a capacitor stores energy in form of electric fields. If there is a path to place some
charges on one side
then it attracts the opposing charges through the other path and charges the other side.
Now even if I cut the paths it will hold on to its energy and the first popular capacitor that was made like
300 years ago was called a Leyden jar
It has quite a simple structure and I also noticed that the king of random Junior made one and I watch the video and
Let's just say I don't appreciate misuse of capacitors
That's quite rich coming from me, I guess and thanks to circuit specialists. I'll give away two hand tech scopes at the end
I mean 200 megahertz two channel scope for [very low price]. What is your excuse for not scoping curves?
Let's make a Leyden jar and explain it
I took a plastic bottle for vitamin pills and peel the label off because they thinner the wall the higher the capacity
I cover the outside of the bottle with aluminum foil as one side of the capacitor plate. Cut the extras
Tape the edges with electric tape
There
Then we put a metal screw or nail
at the center of the lead all the way in so you can get into the water in the bottle later
I can't put metal plate on the inside of the bottle
so instead I fill it with water which is not conductive and
Then add salt to it to make it conductive
So now the aluminum on the outside and the conductive saltwater on the inside are the two isolated
conductive plates of my Capacitor
and now I add some length of metal wire to the end of the screw which will help increase the surface
Contact to the saltwater and reduce the resistance. Now, this is pretty much done
But the actual Leyden jars have a smooth metal
sphere at the end of the rod that removes all the sharp edges where the charges can run away from
I don't have a metal sphere
But I have a ping-pong ball that I can wrap inside aluminium foil and make it as smooth as possible
put the end of it around the screw and
Cover the rough surfaces with electric tape and we're done. Let's see if I can measure the capacitance
According to the meter the Leyden jar is around one-and-a-half
Nanofarads, which is pretty small but it's around what it should be
Now King jr
Used the PVC pipe and rubbed it with paper towel. PVC picks up negative charge and he charged the bottle like this
Which is incorrect. Helping me with the material I need for my video. Thanks King
What is wrong? A capacitor is a two terminal component: if charges come in from one side
The opposing charges need to get in from the other side. The way King jr. Is doing it
it is still getting charged but not as the capacitor it is but as
Anything can pick up charge like this PVC pipe the outer
Surface likes to become positive because the negative charges on the inside of the bottle repel the electrons on the outer surface
But they have nowhere to go until he touches the surface
Try grabbing the foil and then touching the nail to see if I get a shock
Oh? I got a shock just from the foil
That's not how it's normally supposed to go
But so now the jar has a chance to give out some of its electrons to King Junior's body and become positive
while King jr
becomes more negatively charged
now when he touches the center of the Leyden jar
The discharge is not too great because both the center and his body are charged negatively and the remaining energy dissipates through his body.
There was a little bit. Oh, a little bit of a shock. Let me show you how to do it properly
The outer surface is connected to earth which is also connected through this wire to my body and grounds my body
I hold the towel in one hand like this and
Rub the PVC pipe against it while passing it over the center of the Leyden jar like this
now when I do this the PVC pipe picks up negative charges and places them at the center of the Leyden jar which repels the
Electrons on the outer surface into Earth the towel becomes positive
So it sucks electrons from earth through my body and becomes neutral again
So next time when I pass the PVC through it
it can send more charges through. It's basically like I am pumping charges into the capacitor [gets shocked]
I'll have to hold my hand a little bit further
This is very much the same way a Van de Graaff machine works. Do you hear the charges going in?
Okay, let's see if it picked up any charge. [gets shocked more intensely]
I forgot to unground myself
That was painful
No more touching with hand. I made another grounded ball to discharge it. Let's try the different number of strokes
I made it darker too, so you can see the arc
Okay ten strokes
Yeah a little bit. That looked like a one kilovolt discharge
Here's 20 strokes
Not bad was probably around five kilo volts
and here's 50 strokes
Wow that was strong maybe around 10 kilovolts
Okay hundred strokes
Whoa-ho-ho
That was like fifteen sixteen kilovolts. And then the King junior tried to charge his Leyden jar using one of those plasma globes
Which is very much the same as a Tesla coil, and that wont work either
nothing
Nothing whatsoever
the reason is simple something like a Tesla coil outputs high frequency AC arcs while a
Capacitor shorts AC so there wouldn't be any charge buildup on the capacitor
Now I want to see how much current it can send through my body
So I'm gonna use a one ohm shunt resistor in series with my body
so every volt is one amp and twenty strokes or around five kilo volts and measure across the shunt
using my scope
Okay, twenty strokes, of course
This is not going to be super accurate due to the line inductances and the fast nature of the discharge but we'll see
Okay ready
[agonized yelp] oh ****
Wow, it hurts where it goes in and where it goes out to the ground
Of course, this is much worse because it's capacitance is around five times larger than a regular discharge a human body experiences
So the duration of the pulse is much longer and a five kilo volt on this one can hurt as much as twenty five
kilo volt of a regular discharge
I like King junior or senior. Try this one
and if you look at the plot you see there is a
faster spike of up to 12 amps through my body and then the current stays around five amps and
discharges slowly to zero in around seven microseconds
Here's the screenshot if you want to see more accurately. So although the voltage and current are super high
I'm saved by the fact that the pulse duration is very short
So the energy is limited. If the voltage is high the current is high. Now this capacitor works
but it's a piece of junk. Why? Because every capacitor has an equivalent series resistance or ESR that we try to minimize
But this guy has a huge one. The huge ESR contributor of this Leyden jar is the awful
conductivity of salt water if I [gets zapped]
[curses]
Forgot to discharge the damn thing. Let's open it. Now if I measure the resistance between the salt water and the top ball
Around three to four kilo-ohms. It's huge compared to regular capacitors with milli-ohm ESR.
Now I want to make a high voltage high-capacity low ESR capacitor and for that I bought this which is a desk cover made of "material"
I suppose it's some sort of mylar or something
I cut two sheets out of it and hopefully there are no punctures on it
Otherwise the high voltage will always find a way and arc through and ruin the voltage rating
I also cut two sheets of aluminum foil half an inch shorter than the mylar on each side and I'll glue it on the mylar
I put some glue on and spread it in a very thin layer
Then I stitch my aluminum foil on right at the center
And make sure it's completely flat and thin
Very nice
Then I just tape a piece of flattened wire like this to one corner of this sheet
Then I flip it around and glue the next sheet of aluminum right behind the first one
Now I tape another wire to the opposite corner of the first wire on the second sheet
Okay, we have our basic capacitor, let's measure its capacity
At around 5 nano-farad you're already ahead. But now we'll roll this tight this way
the layers will overlap multiple times increasing the capacitance much more
But now that I think about it rolling it should only bring the outer surface of one
Beside the outer surface of the other one. So double the surface area and double the capacitance. Am I wrong? Let's check it.
Crap, I totally forgot first I had to put this second layer of mylar. Otherwise, I would short the two layers
and now we roll again
Ok, let's see what we've got. There you go much smaller than the Leyden jar and it's capacity is
around 10 nano farad much more than the Leyden jar and I think it can still do upwards of 10 to 20 kilo volts
This will take forever to charge using my PVC pipe though being almost 10 times my Leyden jar if this took 20 strokes to get
A decent arc. This will take around 200
Well, I can charge it to 2,000 volts using my microwave transformer through a puny single diode rectifier
Let's give it a try
Okay, is it charged?
Let's see
Ouh it is charged! Well not big enough, though
I really wish I had a Van de Graaff machine so I could charge it to a million volt or more
Maybe I should make one of those
[GIVEAWAY TIME]
The good people at circuit specialists have provided two hantek scopes to give away to my patrons and viewers
I have used this scope briefly before and have seen good feedbacks about it, too
So if you are also into scoping curves
You can become my patron at patreon.com or sign up from the link in the description for free
It is on sale for [very low price]. So, you know how much you can learn by seeing actual waveforms. Do you?
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