it's experiment time again

[DaveinKY]

Matt,
As far as "DC can and will zap the hell out of you also. Touch jumper cables if ya don't believe me." I agree totally with you. As far as the Danger: High Voltage sign, I believe that 95% of common people, people who know nothing about electricity, associate voltage with electric circuits. I don't know how many people would associate "Amps" with electricity. Alot of people hear 120 volts for home use for 12 volts DC or automobile use. I don't think most people hear about 120 volts, 20 amps or 12 volts 10 amps for any practical purpose.

And yes, I actually have seen a sign that says Danger: High Amps. Look inside of an SCR type DC drive. The sign says "Danger: High Amperage Generated in this Area." Again this was only in a specific area and not for "most" people to see.

 

[Anonymous]

Here's a good link on the subject by Mr. Borneman..
http://www.reefs.org/library/talklog/e_ ... 20600.html

It says a 9V current is ideal.

 

[Anonymous]

And one of the original papers...
http://globalcoral.org/reef_restoration ... awater.htm

 

[CiXeL]

havent read all the posts. havent been following the thread because i didnt recieve a notification.

read this:

Shock treatment for coral restoration
http://news.bbc.co.uk/1/hi/technology/3717168.stm

"The electricity costs are equivalent to running a few beach lights. It is only 12 volts so divers are safe."

i have a power supply for OUTPUT: 12V DC 500mA

should that work?

 

[Apophis924]

what about using 18k or higher gold for your golf tee experiment. Gold conducts good current and if you are using a gold/paltium alloy you wont have any problems with metal corrosion. I doubt there would be any problem getting custom pieces made for your experiments. Thought it will cost you a pretty penny to have such "custom " jewelry made.

 

[Fatal Morgana]

A few comments, still need to read some of the links above....

1, 18K or even 24K gold is not very pure. Guess what is that 25% non-gold in 18K? Yes, large portion of it is copper. It is common for most people to suggest titanium/gold/platinium alloy without considering that copper is a common alloying metal.

2, As mentioned above, it does not matter much if it conduct electricity well. In fact, you can even use graphite or pencil lead to mount the coral if you want.

 

[Apophis924]

Pay attention Fatal, the suggestion of 18k or higher godl refers to gold jewelry alloys of platium or normally called white gold. It is called custom made jewelry and if it is possible and the price is right the jeweler will make it out of any group of metals you desire. Push come to shove he can even go as far as using surgical steel acupunture needles Or go with the gold and titanium needles. and yes they should be as good as a conductor he can get a hold of reasoning being...
The better the substance conducts an electric current the LESS voltage one would need to apply for the desired result and when dealign with electrictyone shoudl use the lowest voltage/amps required to accomplish the task.

 

[brahm]

...I thought in the aticles the uses a specific metal.. (could be wrong though), and the volts were 12 and the said it was low enough for the divers not to get shocked or hurt the fish. But the problem with it in aquariums so I read it that there is a bi-product created when you are running the current which you will need to export out of your system.

 

[Fatal Morgana]

I know a thing or two about alloy, and unless I need to refresh my memory, "white gold" is a gold alloy with lots of nickle that give it a whitish color instead of the yellowish gold. It is not a platium alloy. Pure gold is so soft that jeweler usually don't recommand it, and titanium usually is alloyed with other metal to give it strength.

With the amount of electrocity we are talking about here, there is no need to use any special material as long as it is decent conductor. From an engineer's point of view, you only want to get the task done with the lowest cost (material cost, for example), and the amount of extra cost in using non-optimal conductor is nominal in this case.

brahm, yes, if the current (still need to sit down and read the articles linked above... maybe I need to shup up before I dig a hole to big to climb out... ) is DC, and the voltage is high enough, electrolysis of seawater in a enclosed environment is dangerous due to biproducts usch as hydrogen.

 

[Fatal Morgana]

Alright, look at some info. about voltage, and here are the summery:

50 volt or greater can stop a human heart
20 volt or greater can cause arc.

furthermore:

Fundamentally, current, rather than voltage, is the measure of shock intensity. The passage of even a very small current through a vital part of
the human body can cause DEATH. The voltage necessary to produce the fatal current is dependent upon the resistance of the body, contact conditions, the path through the body, etc. For example, when a 60-hertz alternating current, is passed through a human body from hand to hand or from hand to foot, and the current is gradually increased, it will cause the following effects: At about 1 milliampere (0.001 ampere), the shock can be felt; at about 10 milliamperes (0.01 ampere), the shock is of sufficient intensity to prevent voluntary control of the muscles; and at about 100 milliamperes (0.1 ampere) the shock is fatal if it lasts for 1 second or more. The above figures are the results of numerous investigations and are approximate because individuals differ in their resistance to electrical shock. It is most important to recognize that the resistance of the human body cannot be relied upon to prevent a fatal shock from 115 volts or less - FATALITIES FROM VOLTAGES AS LOW AS 30 VOLTS HAVE BEEN
RECORDED. Tests have shown that body resistance under unfavorable conditions may be as low as 300 ohms, and possibly as low as 100 ohms from temple to temple if the skin is broken.

http://www.tpub.com/neets/book1/chapter3/1-40.htm