Engineering

I need some information or guide on how i would create a varaible voltage power supply based on LM317L, the voltage should be adjustable from 1.2 to 12 volts by using the potentimeter build into the breadboard, To test this cruit i have to use a 12 volt 960mW lamp. Thanks

Recently, I was searching through the internet, and I came across a rather strange invention. It is called the O-Zone Lite. (http://www.ozonelite.com/) It claims to kill airborn bacteria, mites, and other nasties like pollen. According to popular science it oxidizes air. How does it do that? NOS? Ozone? Im still skeptical at this point, mainly because if it releases Ozone, then I would avoid this at all costs, but if it truly is safe, and affective at killing the airborn critters, then it might be worth buying.

Tesla coils often enter conversations but so far [i searched for it anyway] i cant see an official tesla coil thread. so i though't i'd start one.... people can learn about making them... post pictures of currently made and working ones and so on and so forth. i was thinking of making one [my first one] and was wondering for some pictures of others and just general advice and stuff!

I wonder in cellular communications, the base station obtained the desired signal from a mobile user from multipath effects, so that Doppler effect due to motion of user and reflection of radio waves by barriers causes a certain amount of interference since different radio rays are not exactly in the same phase as each other. How does the receiver end decode such signals at the demodulation stage? How can demodulator be so smart to decode such signals with so much interference?

What do you actually mean by thermal equilibrium? From what I know, a system in thermal equilbibrium cannot do external work or else it will violate the 2nd law of thermodynamics. And why do we always use Boltzmann statistic to model and derive so many semiconductor equations?

Hmmh. I don't really know where I should put this, could even put it in the GD, put since it has to do with... err, electronics and gadgets, after about 5 seconds of careful consideration, I put this here. Sooo... I've been going to buy a Geiger counter for a long time, and now I'm thinking which model is the best. It would be used to monitor quite low levels of radiation (operating range from 0.01uSv/h to 1mSv/h maybe). A digital display wouldn't hurt either. I have considered the Inspector-model: http://www.geigercounters.com/SpecInsp.htm (you can even buy a nice piece of software for it ) Any better suggestions?

In most modern aircraft the cabin is pressurized. Despite this you still get the caracteristic (and often painful on descent) ear popping. Why does the pressure change when it is meant to be a controlled environment?

I have recently come to know that information can be much faster than light Information takes a few moments to travel from one corner of the universe to the other. Previously I was of the view that light is the fastest thing in the world. Can amy one explain this?

As stated in the question, to me, both actually study the same thing.... What extent do they study differently? Albert

Hey, just wondering if atlantis is possible, and where it may have been or is still, if it comes to it..Scientifically possible?

2 identical pices of steel wire of equal length were used to manufacture two springs. Diameter of the first spring coil was d, diameter of the second was 2d. Both springs were then loaded with the equal masses. As a result, the first spring stretched out to the one tenth of its initial length. What was the percent elongation of the second spring? Any of you genuises know how to solve this question Hope i put it in the rite section.

Ok, so my friend and I finally got a boat running the other day, old 75 hp 2 stroke mercruiser. Its a quick boat, but man is it nasty. Anyhow, getting out on the water, cruising around in the boat has got me thinking. I'd like to understand more about how boats propel themselves through the water. His is a typical outboard engine, prop, etc. One thing I'd like to know is how to determine how much prop size will effect acceleration, top speed, etc? Basically, I'm wanting to learn alot about boats, as we are now thinking of trying to build a custom boat, I need to learn some stuff. Any info would be appreciated.

http://www.popsci.com/popsci/science/article/0,20967,676853,00.html Hey, waddaya think about this bit here?

Switches, on and off... and stuff. Is there a site where you could learn about different switches (since I'm sort of an engineering/electronics newbie)? I have basic information about reed and mercury switches, but some more complex ones maybe? Please share information about unusual switches.

how do motion detectors work? i want to set up some for my shed, i was told little kids can get past them. any ideas thanx

I'm a second semester Electrical/Computer Engineering student at UWF/UF. I'm very familiar (and happy) with my TI-89. However, smoe senior students and instructors say that HP is the way to go in 'real-world' engineering. Is this really the case? If so, which model should I look into? The HP49G appears to be pretty similar to the TI-89, while the HP48GX seems to be more of what I should be looking for. Any opinions?

Today, I noticed an advertisement for the RICOH Sustainable Development Award. I know that innovated engineering is not exactly my field of expertise, but I was compelled by the cause. It is essentially a project for developing innovations that will ultimately lead to a society with sustainable homeostasis (zero environmental impact). It's not so much the money that I'm after, though I admit that it doesn't hurt , but I'm after the recognition that would come from an award like this one. Here is their link- http://www.ricoh-sustainability.com/ Does anyone have any ideas for a project like this one? Also, I can't seem to find the official rules for the c…

I recently received a challenge/project in which I need to shoot a water/air pressure powered bottle rocket into the air and get it to stay in he air for as long as I can while not breaking and egg that has to be somewhere on the rocket. Here are the rules I received. Material: 2- 2 Liter Soda Bottles (minimum) 4 File Folders Duct Tape 1- Large Egg (App. 70 gr.) **No Metal Guidelines: 1- 2 Liter Bottle for Fuselage No more than 60 PSI of air Total Length, 9ft or less Total Weight, 300 grams or less **No Metal, explosives, or other fuel Rules: 2 Chances, 1 with each rocket Add as much or as…

My radio was producing distorted sounds, but when I brought my hand near its antenna the voice became clear.Can anyone explain the reason?

While searching for info on electrical charge distribution at the earth's surface, I identified an application that uses the earth as a near perfect conductor. http//tdworld.com/ar/power_one_wire_enough/ http://www.stonepower.se/Images/SWER.pdf It is a working application that can't be disputed, but I cannot find a geophysics source that identifies the theory for the near perfect conduction. The pdf article notes that the engineers used 0.05 ohms/km at 50 Hz for the design model. All of my reference sources indicates that earth resistance is quite high. Am I missing something, as it seems the earth conduction is different from earth resistance? Any sources …

I came home today and all of my receptacle cover plates were curled up. Is this a moisture problem or an excessive current problem? We just went through a hurricane and it knocked a hole in the roof and could have screwed with some other things. Any ideas on how to prevent this, or what's causing it?

I was thinking about having 555 driver boards custom made and then selling them alone or in kits. Would anybody be interesting in buying them? Depending on the resistors/cap you use it can be made to do a lot of stuff. Some of the more entertaining uses would be driving a flyback or ignition coil. Obviously having them made for cost a fair bit of money so I don’t want to jump in to this if nobody has any interest. So what do you think? Market or no?

What is an energy efficient method for a robot to climbs stairs? I have ideas for a three wheel design (ripped off from Hannibal). And another design that uses a hydraulic or pneumatic lift (but these seem like a waste of energy). Any ideas? Thank You

in a large scale quarry, cutting and dressing one 2.5 tonne block per 2 mins, how plausable is it to use copper tools?

Here is the URL to our site. It's a bit laughable I know, but we are looking for interested persons in the Milwaukee area. http://www.geocities.com/usmc_1371_3/index.html