Engineering

Hi all, this is my first post. Yes I did a search, didn't find quite what I was looking for. Heck, I searched a few university/government sites that weren't that helpful. I'm basically trying to explain the why concept to my coworkers. I'm a crypto tech in the US Navy. I mainly deal with RADARs. My question is to the nature of harmonics. I know that a harmonic is a doubling of the original frequency. Then it doubles again, and again and so on. When you collect this on an RF pan display, you will see one spike at 1000 MHz (your signal), and another at 2000 MHz (your harmonic). They all understand the doubling factor. They are to the point where they understand …

http://www.baytoday.ca/content/news/details.asp?c=6657 ^ Truley amazing. Words fail me at this current time.

http://www.baytoday.ca/content/news/details.asp?c=6657 Can anyone confirm if this is true , it seems amazing but I'm still skeptical about it .

What is the forumla to work out how long it takes to charge a cap to max value? i know there is one because i've seen it before but cannot remember it and cannot find it any books ive got at home nor the net... does anyone know it?

As once again the batteries fail for the digital camera I start to think about the future for batteries. When it comes to current demanding products such as digital cameras they really are battery-eaters... and big eaters at that! All leading battery producing companies are trying to invent a new, better, longer lasting battery, so far they've been able to pack a bit more in, but not enough... there is a big commercial industry awaiting the person who can come up with a battery that lasts 5 or 10 times as long as current ones do. What are your thoughts on the future of batteries? How would one go about making such a better (yet needed) ultra-battery?

Ive been working on a project and seem to have run into a problem. Im trying to wire up a DC motor w/ reverse using two spring push button switches and a single DC power source. I need to wire it up so that when one of the switches is pressed the motor will move foward and when the other pressed it will move in reverse. Ive been working on it for a long while and all Ive accomplished is frying some diodes. Could someone with a better understanding of electronics help me out?

i want to build one. there are plans for a small one @: http://www.unitednuclear.com/accelerator.htm , but they aren't out yet and i suspect they may be somewhat expensive. does anyone know where i can get FREE plans for a particle accelerator?

Can anyone exlpain how a computer the size of a organic cell could perform complex functions or how far we have taken this technology which I think will change the way we live in the imediate future? I know very litte about this science but I find it very interesting.

Hi, wondering if someone can help me figure out a problem? I want to kick on a warning light based on resistance measured between a pressure sensor and ground. This is a 12v DC system. At pressure goes down, resistance goes up and visa versa. So, at 3psi resistance is 300ohms, at 10psi resistance is 80ohms. A gauge interprets this and displays the correct pressure, but I really need a warning light too. How could I trigger a warning light at 3psi(300ohms)? Thanks!

I can't find method to produce a finite element of a bar using a a part of sin or cos as function. I have the linear solution but it doesn't help me. After founding the method i have to produce the algorithm in Mathematica for that. Can anybody help me please?

Anyone interested in or involved with air pollution dispersion modeling is invited to visit the website at: ........ http://www.air-dispersion.com <== click here to learn about "Fundamentals of Stack Gas Dispersion" ... a very comprehensive reference book on dispersion modeling of continuous, buoyant pollution plumes. The website provides a brief description of the book, peer reviews published in technical journals, the book's complete table of contents, and other information. Topics covered in the book include: classifying atmospheric stability; determining of buoyant pollution plume rise; Gaussian dispersion calculations and modeling; developing windsp…

Im thinking to in the future build a small cottage home on a 2.5 acre piece of land that I own. Its across a bridge from a highway, right beside a main road, and is next to a river (theres also a small stream running on one of the boundries. I want to make it an off grid self sufficient home. Im thinking about different renewable systems to supply my electricity, and my space/water heating. I was thinking about using high efficiency appliances and photovoltaic power. I would also consider a wind turbine but the land is on the river valley with a large hill one side across the street. I dont think it would have enough power for all my appliances, and it seems difficult t…

I built my tesla coil, everything assembled to specs which are acceptable by tesla map. Now, I have a lead going from the capacitor to one side of the spark gap, and then to the end of the primary coil. The other lead goes from the cap. to the other side of the sparkgap and then to the beginning of the primary. If i remove the one giong to the beginning of the primary it will throw a spark across the gap. If I have it hooked up, I get nothing. I'm not sure what the issue is....

I'm building a paper raft using 1 sheet of notebook paper and glue. I'm going to put one penny at a time onto the raft to see how much pennies it will carry before water leaks in. What's the most amount of pennies you've heard of being put onto a paper raft?

It's like a laser connected to a radio or something. The lasers oscillate at frequencies that you control using the radio tuner. The laser makes cool pictures, including stars, circles, swirlies, squares, zig zags, etc.

I had read an article about a large microwave cavity but cannot find the dimensions of the room, it isn't available online. http://web.mit.edu/giving/spectrum/spring02/hands-on-learning.html I want to calculate the approximate frequency generated by the cavity and wonder if anyone has the dimensions for Room 26-100? I have heard that amateur radio "microwave" enthusiasts have sometimes turned metal silos into microwave cavities. Microwave is sort of a misnomer as the MIT room cavity could be in the low high frequency range. Does anybody know of other examples of "large" microwave cavities?

I was wondering: How easy would it be to make a radio at home with common materials? And how cheap? This radio would cover as many frequencies as possible... And please, I don't know a lot of the things like "Use a ___ resistor," I'm not that much of an electronics person.

As mentioned in the topic thx

in airplanes, what are verical and horizontal stabilizers for? is it only for changing direction with elevators and a rudder, or can they do something that the wings can't?

Just something I was thinking about: First, the car's an automatic. Don't know if that matters or not. Second, like all cars, it moves forward (albeit slow) when in drive and you're not touching either the gas or brake pedels. Third, this is assumably because the engine is turning and thus the axel and wheels turn. Fouth, when on a hill of certain incline, the car doesn't move either forward or backwards despite it being in drive and niether the gas or brake pedels are being touched. So, if the engine is turning the axel on the level ground, how does it not turn it on the incline? The engine has to be turning something. It can't know when it's sitting on a hi…

I need help with a question and wonder if anyone can point me in the right direction. Two capacitors of 20 microfarad's and 40 microfarad's are connected in series. A constant voltage of 50 V is applied to the combination, it is then removed and replaced with a short circuit. Determine the final charge on each capacitor ?

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Suppose we have a Aluminium on p-Si wafer contact. Calculations have shown that it will form a Schottky junction since the p-doping will move the fermi level towards the valence band, and hence the fermi level of the p-Si before contact will be lower than the fermi level of Al before contact (condition for a Schottky contact for metal-semiconductor). In a non-ideal contact, a thin insulating layer of Si oxide is between such contacts. If the applied voltage with respect to the Si-wafer is 10V, estimate the amount of field-assisted emission current. Also estimate the amount of the tunnleling current. Given that the thickness of the SiO2 layer is (i) 2nm. (ii) 1…

Well, it just so happens that white tail deer archery season is now open in Wisconsin. And with this season come the old wives' tales of the inbred hillbilly emptying the shot from a 20 gauge shotgun shell and firing an arrow in its stead. Well, after pondering this story I decided that a pneumatic arrow launcher would be the way to go.

I'm working on a tribological problem involving a MoS2 coating, molybdenite, but am having a problem finding a suitable value for its elastic modulus (Young's modulus). Anyone got any insight ?