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static electricity generators

ratstar

Aug 20, 2018
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This video has some cool static electricity generators.

But I'm not quite sure how to put them together myself, I'm not sure about what materials to use, but especially I don't know how to connect the anode and cathode.

Any help from anyone would be gratefully appreciated.
 

bertus

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Nov 8, 2019
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Hello,

Did you see his other video:
The power will be very minimal.

Bertus
 

ratstar

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Ah thanks I missed it!

But I've got a slightly different question, you know how dc motors are also generators. is the same true for capacitors? (Electrostatic actuators as generators) That if you dolly the plates back and forth mechanically do you get a charge coming out of it?
 
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ratstar

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Heres another friction generator, looks cool, has a slide style and a contact style.

 

Harald Kapp

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read this...
Read it yourself. The relevant statement is this:
Initially, a priming charge must be loaded onto the capacitors that are subsequently disconnected from the voltage source.
Therefore this setup does not provide charge by simply moving the plates back and forth as you stated in post #3. An initial charge has to be provided externally and is then used to increase the voltage by changing the dielectric constant of the medium between the plates.
 

ratstar

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I wonder what wins out of doing it with a capacitor, or doing it tribo-electric, contact mode.

That contact style looks cool. it would be similar to doing it with a capacitor, because u would set up a heap of parallel plates the same, it could look a very similar machine.

heres another vid on the contact, "tap" style generator.
 
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Nanren888

Nov 8, 2015
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For small Van de Graffs is often mechanical friction at the source, on the belt, then accumulation of charge (with fixed capacitance: ball to ground) ==> voltage increase.

There are many traditional machines that used static.
Google Whimshurst machine?
https://en.wikipedia.org/wiki/Wimshurst_machine
Have you seen the one where two flows of water fall through rings, breaking into droplets & spontaneously charging the vessels?
https://en.wikipedia.org/wiki/Kelvin_water_dropper
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Generator? No.
As in something that converts mechanical energy to electrical?
Also there is an old experiment where you join & separate charges metal balls.
Basically after charging the plates of a capacitor, if you increase the separation of them the capacitance goes down, so for a fixed charge the voltage goes up.
You can also induce charges on adjacent pairs of spheres (touching each other), then separate the pair, so you have effectively charged a capacitor. You put mechanical energy into the system when you separate them from the inducing static charge, or each other: that is opposing the attractive force of the electrical charges. Check out a physics book on static electricity.
Sorry, couldn't find a link just now.
As above: generally negligible amounts of energy.
.
Piezo, as in those devices that help you light your gas. Hit/deform the crystal, voltage results.
https://www.americanpiezo.com/piezo-theory/generators.html
.
Might also want to google energy harvesting, rectennas,
 
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Audioguru

Sep 24, 2016
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Hey RAT, aren't you in Down Under that is summer time now? Here it is freezing in winter (almost Spring) and the humidity is very low so the static electricity doesn't drain away quickly.
 

ratstar

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Basically after charging the plates of a capacitor, if you increase the separation of them the capacitance goes down, so for a fixed charge the voltage goes up.

The *potential charge* or total store stays the same. as d increases v increases, as d decreases v decreases.
as d decreases, capacitance goes up, while volts go down, (like u said...), so it cancels out no matter how far the plates are apart. :)

AudoGuru - if you keep it in a sealed vessel, then its separated from humidity also.
 
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