Build Definition and 466 Threads

How do I build diy laser power meter. I tried shining 5 milliwatt laser on photodiode. Photodiode is connected to led. Led never turned on.

I'm working on a wifi device testing box and made the first prototype of the Faraday cage. I need holes because of cooling. For this reason, the box has 3mm diameter holes on the top. The box made from steel, and have 2mm wall thickness. The wavelength around 12,5 cm for 2,4 GHz and 6 cm for...

Hey guys I want to build electromagnet which can lift up to 3 kg from 26 gauge copper wire, 12V battery (bike), so how many turns should I do and what will be length and radius of the solenoid?

Okay I have two questions that I plan to post separately. The first question is simple: what elements will be needed to further space travel in the future? Does anyone care to comment on what base elements would be necessary to build the starship Enterprise? I should explain the reason why I'm...

I have a little heating pad 12" X 15" runs on AC 120 volt has around 220 ohms resistance on low final got to hot burned up wire. What to replace it with using junk box parts light bulb wastes 10% for light would need metal cage to keep bulb from breaking seems like not good way. Have 300...

What are are your thought on the future of energy on Earth? Personally, in the long term I believe that Dyson spheres would be more useful and allow us to terraform other planets and became a multiplanetary species much quicker and efficiently, but what are your thoughts?

I am trying to build a radio to transmit morse code. I have built A wien bridge oscillator on a breadboard. I think the wien bridge Oscillator works. How long should The antenna be?

I'm learning about imaging techniques and projection/deprojection for images of galaxies at university. The big issue there is the fact that an image is a 2D representation of a 3D object (for example a galaxy), and to learn some properties of the object you need the 3D structure. What happens...

Can you build a fm transmitter with A crystal oscillator? I already have a 100 megahertz crystal oscillator. I can't find instructions on how to do That on the internet.

I got a chemistry degree a few years ago bit I didn't use it to get a job since I've been doing other things. I love working in the lab and would really love to build up my skills but I don't see myself getting a paid chemistry job any time soon so looking for another way to gain lab experience...

Yes it sounds like I've lost it but I really want to build one. I was wondering is someone could guide me to useful resources. I'm currently reading some patents I found online to gain some more insight. Any help would be appreciated. Thank you.

Hello there, I am studying Taylor series, and in the slides given to us we calculated the taylor series of ln $(\frac{1+x}{1-x} )$ = ln(1 + x) − ln(1 − x), by using standard Taylor series of ln(1 + x). The notes then proceed to say : " It can be shown that every positive real number t can be...

Homework Statement The volume and dimensions of the cylinder are given, and the air is supplied to the cylinder at 4 bar at room temperature.Is there a way to find out the time it takes for the air pressure in the cylinder to increase to 4 bar? Homework EquationsThe Attempt at a Solution From...

Homework Statement The windows in your house will all have two panes of glass, separated by a thin layer of gas. It would be much simpler to just glue the two panes of glass together. Why does separating them with a layer of gas improve their thermal insulation? a. Although the gas has the...

It seems it is time to upgrade my 32-bit AMD Athlon 64, 2 GHz with 2 Mb RAM and 2X 80 Gb hard drives. The programs (mostly browsers & Windows 10) are just too demanding for my little machine which starts to show signs of fatigue anyway. I kept pushing this time as long as I could, mostly...

While reading http://www.dartmouth.edu/~sullivan/22files/System_analogy_all.pdf article, i encountered the following sentence: Thus, we see that K is analogous to 1/C , which makes sense, because with a given current for a given time, a smaller capacitor will build up more voltage, whereas with...

Homework Statement For a given ##a##, define $$B[u(x)] = u''(s) + \cos^2(a) u(s) - \frac{1}{2s_0}\int_{-s_0}^{s_0}(u''(s) + \cos^2(a) u(s) )\, ds,\\ s_0 = \frac{1}{\cos(a)}\arcsin(\cos a)$$ subject to boundary conditions $$u'(s_0) + \cot (a) \cos (a) u(s_0) = 0\\ -u'(-s_0) + \cot (a) \cos (a)...

I understand the following image as follows: There is a build up region that varies with photons energy, the Dmax for 6 MV photons is around 1.5 cm. The build up region means that kerma > dose in that region, meaning that photons are creating electrons and when the Dmax is reached it is going...

Hi, I have an old system that outputs a stereo audio signal (using Left and Right RCA audio cables). However for some reason this system is also outputting a high-frequency noise on both channels regardless of its operation. At this point I think it would be simpler to build a simple audio...

I recently had an MRI scan, and while I was inside I began thinking about how the thing actually worked, and what it would cost to build. The hospital staff told me that the cost was several million dollars, and subsequent research seems to confirm that the 'average' MRI scanner cost between 3-5...

Hello PF, I am considering some options in my upcoming PC build and want to choose the one that performed best in MATLAB. What I mostly do is velocimetry with a big amount of points, image processing, statistical analysis. My options are between 2 CPUs: AMD Ryzen 2700 - for the 8 physical...

Does anyone know if there is a textbook on the design and construction of high frequency oscilloscopes (up to 10 GHz)? I am guessing they would be some form of ADC circuit with perhaps a mixer and could use a lap top as the "DSP" and display. How would such an O-scope be calibrated/tuned...

Mentor note: Thread moved from Mathematics section, so is missing the HW template John and Eli are playing a game with a hall that can roll into one of two pockets labelled H and Y. John wants to keep the hall in H and Eli wants to keep it in Y. When it is John's turn to play, ifhe finds the...

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > a) Using the Yenka (or similar) simulator, you are required to build an RS flip-flop using 2 NAND gates, switches, LEDs and 330Ω resistors. Test the circuit and prove its correct operation against the...

We have a simple table , for example a kitchen table, with some objects on it. If we consider the table having two dimension (1) does the table with objects represent an affine space ? Why ? I want to do some calculation, so i choose a point as origin and i place a vector space in the affine...

If someone, were to theoretically build a microscope that could see an atom what, would the electrons be doing?...would they be orbiting the nucleus at a steady speed or would they be popping in and out of existence in their shells in different locations due to the uncertainty principle?

This year I made a resolution to by the end of summer build an Android app for my Uncle’s bussiness (Rent-a-Car) which would help him organise the dates of booking a car. I have previous programming experience with C and C++ but not with app creating. The idea for the app is really simple but...

I was at CERN and remember reading somewhere that it is possible to build a cyclotron for the price of 17 US dollars, if anyone has any useful links they could send my way (to blueprints or useful diagrams, it would be much appreciated thank you) :)

Hello, I am interested in making a homemade radio receiver out of common materials. Do you have any suggestions or websites I could get some ideas from? Thanks. I.

Hello. I want to be able to create any mathematical equation or expression. So, one thing I want to confirm is that, to create any complex equation or expression, I should make use of Order of Operation - PEDMAS or BODMAS. Correct? The Order of Operation governs the result, and the Order of...

Hi guys, so I am building this light fixture as a concept an inside of the light fixture is a sealed cavity which houses the power supply and control gear. Now to service this unit that cavity opens up, but let's say on a hot humid day the unit is opened and that air enters the cavity. Its then...

Came across a pair of websites claiming to be DIY Quantum Entanglement Experiment. Problem is, I don't know how realistic it is. Essentially, is this real, or am I being taken for a fool? Part 1...

I want to build a computer simulated wind tunnel. I have experience building physics simulators. I undersand that there are already some existing free wind tunnel simulators out there, but do they work at supersonic speeds? I want to predict the drag coefficient of various rockets and bullets at...

Ok so here it goes, I have a motorbike,and as I am a learning engineer I want to build a second engine for a few reasons, firstly I want to go faster secondly I want to do all the work myself to learn, thirdly I want to become a better engineer and want to do lots of paper work to learn and see...

Hey! I posted this thread hoping that there are experts about quantum physics here. Please if you do not know a lot about the subject, don't answer this question: First things first, to be clear: I’m NOT building a quantum suicide machine and I’m NOT trying to kill myself. I’m just curious...

At my school we have started a program where we have one class a week on building circuits and playing eith the applications of circuit parametres. I would like you to tell me if there is a program, website or an app that can provide me with lessons or ability to build circuits of my own and...

Homework Statement For school, we have to build a mousetrap car, and get it to go 3m. Our car doesn't roll very well, and we aren't quite sure of the problem. We have an axle that is 5mm wide, and the thing that holds it to the chassis is made of cardboard. Also, the mousetrap is pretty far...

Might sound really stupid, but will it be more economical if instead of wall, a WIDE trench filled with water from adjoining ocean and river is allowed to flow in. With both the ends of the trench connected to the ocean, we can allow water to flow in during high tides, and flown out during low...

Homework Statement [/B] Build a linked list with values of 1, 2 and 3 The Attempt at a Solution class ListNode(object): def _init_(self,x): self.val=x self.next=None root=ListNode(1) root.next=ListNode(2) root.next.next=ListNode(3) print(root.val) I keep...

I'm currently an Aerospace major/Physics minor who's interested in delving further into mathematics. What is the optimal sequence of topics that I should follow for self-studying. I know this forums has links to a lot of interesting books, but I don't really know which one to start with. Thanks...

Is it possible to build the full wave function for a simple problem in QM, such as an infinite well, without any experimental data ? I'm learning about QM, and I saw how to compute energy states (the wave function for each allowed energy level) in some usual QM basic problems. But then, I was...

The reason I ask is that when we use the surface of the Earth as an analogy, if we travel in one direction then eventually we will come back to where we started. But to do that we need a compass or some similar instruments to keep track of our path to make sure we are always in a "straight"...

Hi, Thanks for all the kind help answering my goofy questions guys. Here is the results. This is a reproduction of a 1956 Fender Deluxe with modern case covering. The cloth is seat cover material from a vintage Porsche 911. The sides are black leather. Minor change to the the grid...

Homework Statement . Your physics teacher has assigned you the task of building a water ba,rometer. You've learned that the pressure of the atmosphere can vary by as much as 5 percent from 1 standard atmosphere as the weather changes. (a) What minimum height must your ba,rometer have? (b) One...

Hello people, i was thinking about building a homemade particle accelerator but i do not know the materials and specifications to build one, can you guys help me know what thing do i need to buy and how to make one? Thanks

Curiosity question: What physics knowledge would be required to build a house? I am not going to build a house, this is just a question out of curiosity because it may not look like, but I think that a well built structure may actually be something complex that employs many physics concepts...

Homework Statement Given the points ##A (1, -1, 0)## and ##B (4, 0, 6)##, find the point ##P## of the line ##s## so that the triangle ##ABP## is a right triangle in ##B##. Calculate the area of the triangle. ##s : \begin{cases} x = 1 + 4t \\ y = 2 - 3t \\ z = 3 \end{cases}## ##\vec v_s = (4...

So, my SPS group is building an optical and a radio telescope (using a typical TV dish). The trouble is, these are merely for showing kids and sometimes for us to just see the sky. Because of their small size, we won't be able to do a lot of research. What I need is a telescope like the...

Sam Harris had a TED Talk on this not long ago. What do you think? Are we taking the dangers seriously enough or does Sam Harris have it wrong?

I like to skate around abovetopsecret.com without actually falling in. ;) One of my favorite chunks of weirdness in that soup of insanity is the idea that the Moon is actually a spaceship. Some say it was put here to help create conditions conducive to life, to stir the primordial soup and all...