Device Definition and 531 Threads

Homework Statement consider an ideal hampson-linde cycle in which no heat is lost to the environment. Argue that the combination of the throttling valve and the heat exchanger is a constant enthalpy device, so that the total enthalpy of the fluid coming in this combination is the same as the...

I want to start an electronic company, but I don't know what are all the types of engineering jobs that are capable to build an electronic device (Ex: Cell Phone, Tablet). When I get to University, I'm planning to make some friends who have a degree on it. Also, I need to know what the jobs...

Hi everybody, this question is on an old exam paper given to us for exam prep purposes. No answers have been supplied however. Am I on the right track? Question: A mass of 0.2kg of saturated refrigerant-134a is contained in a piston-cylinder device at 200kPa. Initially 75% of the mass is in...

hi all, i am looking to build an ultrasound producing device that emits at 50,000 cps? i need a list of materials and how to construct the circuit. research shows that you can multiply the growth of plants (radishes were tested) by 150% if subjected to ultrsound at around 50,000 cps. thank you...

Hey all, I'm using a peltier device for a cooling system I'm working on. The metal leads connecting the peltier to a power source keep falling off. I am looking to coat them with epoxy that must be a thermal insulator. It also MUST be an electrical insulator. The problem I've had is that...

Is there a hand-held device measures the percentage of radiation in the human body?

What possible device out there that can make me give a constant power to the cue ball (the white one) as i break the rest of the balls? Like is there something automatic or something becuase this is for an experiment i want to do advice pleasez thnx

I've read that supposedly no coherent information can be instantaneously teleported across space between single pairs of entangled particles because of random fluctuations. But might a way of overcoming this be to take two separated sets of more than one pair of entangled particles and arrange...

Greetings, I've just learned some of the basics about thermoelectrics, and I often come across a diagram that confuses me (see the third and fourth figures in the http://en.wikipedia.org/wiki/Thermoelectric_effect#Charge-carrier_diffusion"). All of the literature I've read refers to the top...

Where would i start to create a cheap device that has a usb input and usb output, the device when plugged in a tv (that doesn't play video files from a plugged in usb) and another usb with a video file, plugged in the other side of the device, will allow the tv to read it and play the video...

Homework Statement http://img841.imageshack.us/img841/4725/device01.jpg (I hope I translated it correctly, this has some technical terms...) This device is used as a key for installing a disk on a stational shaft, O. The device is equipped with pins A and B, that goes into the holes of the...

Hello I'm looking into ideas to make a device which can lower a small object which is at a certain distance from the ground. I was thinking of it being lowered by the action of putting some sort of weight in some sort of bucket (likely water as weight). I just can't think of how to make it...

A few shopping centres in my area have these devices that can measure your weight and height. I figured I'd try it out, all you had to do was insert a $1 coin. Thing is, it has this type of tube on the top of it (the actual device was in an elongated C shape with a small platform to stand...

A cylindrical tank of radius " r " contains water upto height " H " . There is a hose at height " h " from the bottom. At what angle should the tank be inclined (Of course in the direction of the hose) so as to double the water output from the hose? N.B. Assume necessary simplifications

I don't know a lot about PLD's so hopefully someone here can help me. Is there a relatively cheap PLD that can switch between 2 inputs every given amount of time, like every second or every 5 seconds? I'm just trying to find what I am looking for and can look up and read through the data...

3.A cylinder/piston arrangement contains 5 kg of water at 100°C with x = 20% and the piston, mP = 75 kg, resting on some stops. The outside pressure is 100 kPa, and the cylinder area is A = 24.5 cm2. Heat is now added until the water reaches a saturated vapor state. Find the initial volume...

Greetings. I am a woodworker, and i build lockboxes with hidden compartments and complicated homemade magnetic locks. On my current lockbox, i am trying to design a "box of compartments", 16 compartments to be precise. included is a quick top view (looking down) design. there are actually 15...

would a 1.5 volt electronic device that measures capacitance to turn on or off a regulator that controls water flow affect a defibrillator or pacemaker? Another way to ask this, A kitchen faucet that is touch sensitive would be safe or not safe for a heart patient who has defibrillator and...

Hi friends! I have recently started a small project where I had hoped to build a simple sun tracker. My initial plan involved 2 Photovoltaic cells mounted at either end of a panel which was attached to a shaft which was then attached to a small DC motor. Both cells were hooked to the motor...

http://www.bbc.co.uk/news/technology-12453893 I ran across this article and found it to be quite interesting. I am not academically versed to understand the physics of this application, but it seems that it could have huge impact within the electrical and electronic engineering fields. How...

Hello, I need some assistance building a device. I want to input a voltage below 5v, process it and manipulate it by a programmed amount. It won't be perfectly even so I can't do it by a set resistance, meaning the scaling will be different. Example: input 3.74v process it as 73 degrees, then...

Homework Statement A demonstration device consists of two parallel metal plates separated by an insulating support. The device is placed on top of a negatively charged van de Graaff generator. In between the plates are several Stryofoam balls covered with metallic paint. a) Describe what...

Hi, I want to power a wifi device using solar power. But I see the datasheet which has input voltage -48 VDC. I am confused on how to power this system using battery ? Any suggestions are welcome. Thanks a ton...

Is op amp or any amplifier circuit/device a over-unity efficient device? The above question has been stuck in my mind, and I can't figure it out, as Vout is greater than Vin which Pin>Pout. So is it? I heard a lot about free energy and aether, thus come to this question.

http://img522.imageshack.us/i/0108111458.jpg/ I found this weird mechanical device in the woods near my house. There seems to be some kind of serial number on it that reads, "DY6-6" http://img828.imageshack.us/i/0108111753.jpg/ It also says, "MADE IN USA" on the other side. The flywheel...

Do any devices exist that can assist your arms in exerting a force of 160 lbs or more in a direction of such where you would have your arms extended and move them up and down, like flapping wings for example, to the effect that you would be using the minimum amount of effort required which would...

In the double slit experiment - what exactly is the measuring device? .. the have to measure witch slit the photon went trough - how do they do it? - measuring anything means interacting with it. Changing it, really. So, isn't it obvious that interacting with the photon in any way will...

Are their any devices currently available that can assist a human in exerting a force of 700 N or greater? Exactly how much force is 700 N equivalent to? Hydraulics are the only thing that comes to my mind, is their anything lighter? What do exoskeletons use to assist the user to lift greater...

so i have a device which uses 2 AAA batteries. i don't like charging batteries all the time so instead i want to power the device via usb. a AAA battery: 1.5 volts and 300-1000 mAh (milliampere hours) usb has 5 volts and max current is 500-900 mA how do i do this?

While posting a reply in another thread, I had an inspiration for a device to measure spacetime curvature. It is well know that we can measure this curvature by measuring the angles of a large triangle or comparing the circumference of a circle to its radius, but his device may may be simpler or...

I'm looking for a device that can record EM signals of unknown frequencies (unknown to me) emitted by devices. For example if I point my remote control at it and start pressing buttons it should record intermittent IR frequency surges. Or for example if I build an emitter to modulate an...

I bought a camera in France and I want to use it in Canada. The main problem is the battery. To reload it (I think it's a lithium one but I'm not sure. I can check out if you need this info) I must plug it into the AC current supply at home. In France it works at a different frequency I...

Little preface to this series of questions, I'm really into theoretical physics but I have very little astronomy knowledge. I'm a very curious person so feel free to talk over my head and I'll google what I need. That being said, I'm participating in Novembers "Novel Writing Month" as a fun...

hi, with reference to my last post on oct 21, https://www.physicsforums.com/showthread.php?p=2951801#post2951801 would anyone be able to tell me what the actual name or specification of the ceramic used in a peltier? Cheers, John.

Homework Statement A piston cylinder device with a spring attached initially contains 0.02m^3 of R-134A at 50C. A valve connected to the cylinder is opened and 20kg of R-134A enters the device from a supply line at 800kPa and 80C. The spring is compressed and the piston moves up. The process...

An egg is hard, but yet delicate food that people have been making contests of, for many years. But i am part of one that i lack the physics to figure out the perfect device here are the simple rules of this contest. Holy Omelets Batman… It’s the Egg Drop Contest! Design a egg protection...

Suppose there is a quantity X to be measured. To do this you have a measuring device with a resolution of 1 and an accuracy of +/-1. It is imediately obvious that repeated measurements can yield an accuracy of +/- 0.5 but can any greater certainty be achieved? If 2 measurements are made and...

Hi all, Im currently working on a project that requires me to continuously measure the density and thickness of a sheet during an extrusion Styrofoam process. I have researched sensors and have found some that will do the job but of course they are in the $10k range. These however only...

I wonder if this is available on the market. I would like to have a ''digital notepad'' with a computer screen on which I would be writing with a digital pen (with a screen 8 1/2 '' x 11 '' in size or about). Whenever I look for a ''digital notepad'' or a ''digital tablet'' I get devices where...

Homework Statement A piston–cylinder device initially contains steam at 3.5 MPa, superheated by 5°C. Now, steam loses heat to the surroundings and the piston moves down hitting a set of stops at which point the cylinder contains saturated liquid water. The cooling continues until the cylinder...

Homework Statement You are given a device with which to operate with an input resistance of 50 W. The device requires 9 V to operate. However, the only available power supply is a 12 V source. Part A:Using only resistors, design an interface circuit to lower the 12 V to 9 V for operating...

Hi, I am trying to design a small machine that lowers a raised weight slowly. For example if i raise the weight by 10 metres and allowed there it should start descending at 0.1m/hour. Initially i thought of a windup mechanism but i don't know how to control the rate of descent with a windup...

Does anyone know the name for a mechanical device where a ball bearing is made to go down a ramp, through loops, up and down pulleys etc, while moving on a metal rail? My first thought was a Rube Goldberg device, but I don't think that's it. Richard

I'm looking for some input on the design of a lifting device. The design is required to accurately lower lower a load of 400 metric tonnes through a height of 50m, return to the top of it's travel and lower the next load and so on. I'm currently thinking along the lines of a two-pronged tower...

I would not agree with this device being used over seas much less in our own jail systems. http://news.yahoo.com/s/ap/us_jail_ray_gun Why don't we just launch an inquisitor program?

we are required to do an egg drop. all we are allowed to use is 2 news paper spreads, 2 m string, and masking tape. what's the best way to use these materials in order to be able to drop a hardboiled egg from a 4th floor without any cracks. thanks!

Hi i have 3 wire ropes that holding a weight and i want to have the same tension in all of them. there are some devices all ready in the market bat costs a lot of money.. 500 dollars/euro and more like this onei was thinking to build my own device.. like this one : screw with my Torque...

Does anyone know a device that reads the frequency of objects? I want to be able to read the frequency of a glass plate and a sheet of aluminum. What is it called?

Does there exist a device that can be put in a fire or other hot heat source to generate energy? I'm looking more into if a portable or smaller device fits this category.

I have what is likely a very stupid question, but here go's. I was sitting around and got thinking how I might make a better generator. One that doesn't develop opposing torque on the armature when it is under load. How would the laws of conservation come into play if I were to build a...