Morgan - 3-9-2011 at 07:08
I was toying with an electrophorus I made out of an old turntable. It makes some good two inch sparks merely by lifting the aluminum disc off the
surface of an acrylic sheet/dielectric about a tenth of an inch thick with a two pound coffee bag I unfolded and put underneath the acrylic sheet-
it's a metalized plastic bag with glued seams and a vacuum sealed bag. Regular aluminum foil works about the same but I wanted to see how other
materials perform.
I was hoping to enhance the electrophorus effect by using the same philosophy as this shampoo bottle which is much smaller in surface area.
Does anyone know anything about surfaces treated with cornona discharge to paint plastics that are difficult to paint?
http://www.esdjournal.com/static/shower/shower.html
I came across this other electrophorus design where he starts a fire with it.
http://www.ece.rochester.edu/~jones/demos/kamachi.html
Back in the old days ...
"Today it is so common to produce light just by turning a knob or pulling a switch and it
is so easy to produce a flame with a very cheap box of matches or a disposable plastic
gas lighter that we can hardly imagine how problematic it was in the past to obtain the
same effects. The history of fire-making appliances dates back to prehistory and is
marked by a large number of artefacts (tinder, flint and steel, quartzite and iron, matches,
etc.) and methods (friction, chemical, pneumatic, etc.), which were often unreliable,
inconvenient or dangerous."
"In this article I would like to retrace the evolution of a very peculiar fire producing
apparatus which was invented in the late 1770s and remained in use up to the middle of
the 19th century: the hydrogen electric lighter. The first lighter of this kind was conceived
by the famous Italian physicist Alessandro Volta (1745-1827) but subsequently it was
essentially in Germany that this useful device was largely improved and modified. This
lighter became the first electric household appliance, one of the very first “push-button”
(or at least “turn-key”) apparatus."
"However, another Volta’s invention of the late 1770s, the electric lighter2, even if from a purely scientific
point of view it could be considered as a cabinet curiosity, nevertheless became very
popular."
"In Autumn 1776, while still professor of physics in Como, Volta collected a gas the
so-called “aria inffiammabile delle paludi” (methane) bubbling from the water of the
Verbano Lake and soon he discovered this gas was flammable and could be ignited by an
electric spark.3 At the same time Volta was also experimenting with another gas: the
“flammable air” (hydrogen), which he ignited in his famous electric pistols (with all the
possible variations of this quite innocuous laboratory weapon: electric cannons, electric
guns, electric mortars etc.).4 In May 1777, in letter to the Marquis Francesco Castelli, he
mentioned for the first time that he was elaborating a new invention: a methane gas
lamp.5. Almost a year later, in April and May 1778 he wrote a series of letters to the
Geneva naturalist Jean Senebier (1742-1809), in which he mentioned that he had
perfected two kinds of lamp. The first one was burning methane and could produce light
for one hour with a “jar” of gas, while the second one was in fact a hydrogen lighter
(briquet) which could be used for igniting a candle or a waxed wick. The latter was
portable and could be ignited with the spark of a pocket electrophorus (invented by
Volta himself in 1775)."
"Even though Volta never considered his lighter to be one of his major inventions
(even before the invention of the electric cell), nevertheless he was quite proud of it,
considering that it was not only an amusing curiosity but also useful and practical
device."
http://www.sci-ed.org/Conference-Pognana/Brenni.pdf
Another design.
"In 1777, he built a large electrophorus in order to generate static electricity through induction.[2] One of the largest ever made, it was 6 feet (2
m) in diameter and could produce 15 inch (38 cm) sparks. With it, he discovered the basic principle of modern Xerography copy machine technology. By
discharging a high voltage point near an insulator, he was able to record strange tree-like patterns in fixed dust. These Lichtenberg figures are
considered today to be examples of fractals."
http://en.wikipedia.org/wiki/Georg_Christoph_Lichtenberg
http://www.electrotechnicproduct.com/corona.html
Also, I was wondering too if an elctrophorus would produce x-rays if lifted off it's surface in a vacuum? Recall the Scotch tape experiments ...
Sticky tape X-Ray
http://www.youtube.com/watch?v=r63e5y3Z3R8
Here's a couple of youtube videos with very small electrophorus examples.
http://www.youtube.com/watch?v=TO95iGtRVv0
http://www.youtube.com/watch?v=2Fhoi1gumHY&feature=fvst
I want to beef up my dielectric like the shampoo bottle article where the plastic was treated wtih a corona discharge to get the metalic printing to
stick, but also created a great shocking hazard. Apparently you can use various waxes and resins and create a charged material too if you read the
Homemade Lightning topic.
http://books.google.com/books?id=V8Hq_Kg1s9sC&pg=PA135&a...
Volta tidbit.
An additional invention pioneered by Volta, was the remotely operated pistol. He made use of a Leyden jar to send an electric current from Como to
Milan (~50 km or ~30 miles), which in turn, set off the pistol. The current was sent along a wire that was insulated from the ground by wooden boards.
This invention was a significant forerunner of the idea of the telegraph which also makes use of a current to communicate.[7]
http://en.wikipedia.org/wiki/Alessandro_Volta
[Edited on 3-9-2011 by Morgan]
Morgan - 3-9-2011 at 13:22
Conflicting triboelectric series data.
http://www.siliconfareast.com/tribo_series.htm
http://en.wikipedia.org/wiki/Triboelectric_effect
"Inaccurate information about air being "positive", etc.-- A triboelectric series table has been circulating on the internet, and it contains various
inaccuracies. Though attribution is rarely given, it appears to be mostly from a 1987 book. It lists air as the most positive of all materials,
polyurethane as highly negative, and various metals being positive or negative, apparently based on their known chemical electron affinities, rather
than on electrostatic experiments. (From actual tests, there is little or no measurable difference in charge affinity between different types of
metal, possibly because the fast motion of conduction electrons cancels such differences.) In gaseous form, air is generally unable to impart any
charge to or from solids, even at very high pressure or speed. If chilled to a solid or liquid, air is expected to be slightly negative, not positive.
There are three cases where air can charge matter (in the absence of external high voltage). 1. If contaminated by dust, high-speed air can charge
surfaces, but this charge comes from contact with the dust, not the air. The charge polarity depends on the type of dust. 2. If air is blown across a
wet surface, negative ions are formed due to the evaporation of water. In this case, the wet surface charges positive, so the air becomes negative. 3.
If air is hot (above about 1000°C), it begins emitting ions (both + and -.) This is thermal in nature, not triboelectric."
http://www.trifield.com/content/tribo-electric-series/
static generator
http://www.youtube.com/watch?v=tzbAZ7eX_i4&feature=chann...
[Edited on 3-9-2011 by Morgan]