Device Definition and 531 Threads

how to make auto-switching device using transistor??

Homework Statement See figure. Homework Equations The Attempt at a Solution I tried KVL (see figure), but still got stuck with only 1 equation and two unknowns. Any ideas/tips on what I should try next?

Homework Statement See figure Homework Equations The Attempt at a Solution Again, see figure I tried something and it looked promising but the answer doesn't work out. Any ideas?

Will this power supply work for my device? URGENT! I have a Mini-fridge I need to get usable again. Recently, as of a few minutes ago, I opened up its power adapter to find that capacitors have burst and that would be the reason of the fridges death a few months ago. Given the mini-fridge is...

Homework Statement Describe how a venturi device for measuring the flow of water in a pope works and estimate the slowest flow rate such a device could be expected to measure using 20% of cross sectional area constriction and a mercury manometer. Homework Equations A1V1=A2V2 I also know...

"GPS" device & connections Instead of using the satellites like Google Maps, is it possible to come up with a device that any device, such as mobile and laptops can connect and communicate with the device? In other words, let say Harvard campus. We know its campus is very large in terms of...

hello everyone i am doing my intern and am told to come up with a design for a device adjustable in height and width. i have been looking on the internet and found some designs that might work but the problem is i don't know exactly how does they function. for example this design ...

Hi guys, I don't understand why when one touches both the live wire and neutral wire in the secondary of an isolation transformer, the current in the live wire and the neutral wire in the primary will be the same. This is described in my book as the reason why a residual-current device in the...

I am currently working on a project that will be a flying device, so i require a bit of range for control. I have been looking around for control systems, and have come across the XBee-PRO 802.15.4 RF Modem, which seems to me to be the best solution for me. Has anyone used this device before? If...

Hey guys, Earlier this week in my meteorology class we learned a lot about lightening. Basically we discussed how the lower clouds in the storm are heavily negatively charged, and when lightning strikes the ground it is looking for a positively charged area to strike upon due to the fact that...

Homework Statement An electric device delivers a current of 2.44 A for 55.0 seconds. How many electrons flow through this device? Homework Equations The Attempt at a Solution I am clueless, i need help

what can i do with a current source from 5ua to 270ua if i want some sort of active digital components

Device that catches an egg! We have a physics project. We are droping an egg from 9.91 meters. We have to use a device that will catch an egg from that height. We can use anything that we want to use to catch the egg. I am trying to get the least height. What materials should we use or...

I'm sure this is very simple for everyone here. I need to make a device that will allow an LED to flash at very specific rates (for example 4 times/sec). I assume I need to use an I/O system that will allow me to program it via computer connected by USB. If this is even the best way to go...

I have six usb ports in all on my system. 2 in the front and 4 at the back. Now if I go into device manager (in windows xp professional sp2) and check under "Universal Serial Bus Controller" I get the following:- Intel(R) 82801 EB Universal Host Controller - 24D2 Intel(R) 82801 EB...

Hi, Some of the ICs for a portable device I'm making need to be attached to ground. However, the device needs to be wireless so I can't ground it the way we usually do. Is there any way around this, such as a circuit that could somehow act as ground? Thanks.

Hi everyone, I am student of Ocean Engineering and now I am in process designing a model of wave power plant based on OWC. For that, I need Wells turbine for generator. I don't have many experiences in electricity engineering so do anyone have diagram to build simple Wells Turbine ? Thanks...

I was just thinking about this the other day... Given any 'blackbox' circuit, for which the values of the thevenin voltage and thevenin resistance are known. And given that a non-linear device is placed across the terminals of the circuit. What relation would one use to find the current...

I'm don't think these people were joking when they wrote this article: The article is filled with claims like this from all over: If it is a make people stupid weapon, it seems to be working quite well.

Hey guys...i'm trying to locate a servo or similar device that has just three basic stipulations... It needs to: -Be able to turn a thin 6 inch diameter plastic wheel (negligible weight, no resistance as it's not attached to anything but the servo) -Complete at least a half revolution in...

hey guys i am trying to deflect charged microparticles inside a tubed device... the device looks like a horizontal Y... the microparticle solution in DI water is sent through the base of the Y...and i am trying to deflect them to either one of the two branches at the other end totally... i...

There is nothing I have tell before I go about on this madcap search. The problem is that I'm only 12 and searching for a device (or a circuit) which changes, or swaps, polarities, every time the switch (a switch made from a phototransistor and a resistor, in essence, getting activated...

I'll try to keep this concise. I am trying to build a alarm system for the DAQ system in my lab that will be software (LabVIEW) based and will replace the current hardware tripped alarms. Right now I am working on a final fail-safe alarm to protect against the freezing of the "alarm server"...

What is the most powerful battery or way to store energy? I have an idea but I wanted to see what you guys would say :)

Homework Statement A closed system comprising a cylinder and frictionless piston contains 1kg of a perfect gas of which molecular mass is 26. The piston is loaded so that the pressure is constant at 200kPa. Heat is supplied causing the gas to expand from 0.5m^3 to 1m^3. Calculate heat...

[b]1. Homework Statement A piston-cylinder device contains 0.05 m3 of water at 200kPa and 25ºC. The cross sectional area of the piston is 0.25 m2. Heat is now transferred to the water, causing part of it to evaporate and expand. When the volume reaches 0.2 m3 the piston reaches a linear...

I'm looking for a device I can use to measure analog voltage (up to 25V) and send the data to a PC via USB. Only really need one input, though it wouldn't hurt to have more. My main concern is that it needs to be pretty small and light - any ideas? The few I've seen online are either too...

The model is a vampyr 731i electronic I can't find the technical information online Howstuffworks.com only gives the information that the fan motor is electrical What sort of motor is used in the lead retraction device?

Homework Statement Four devices are connected in series across a voltage source of 120V. The total circuit current is 4.5A. One device fails to operate. The voltage across each of the other devices is 40V. What circuit fault is indicated and where? Homework Equations E=IR I=E/R...

hi guys i want to make a device consists of - a motor - stick (60 cm long, 0.4 Kg) - remote control - step motor to pull a rope -buttries the idea is the main motor rotates the stick for seconds or for a minute. and the step motor pulls the rope 360 or 720 degrees. and all these...

I've heard that frequency differences can cause the motor to rotate 17% slower than it normally would... UNLESS it is a universal motor. The device in question is listed as running on a universal motor, but is also listed as AC / 60hz only. Does this still apply? Thanks.

http://web.mit.edu/newsoffice/2009/braille-0821.html" MIT students develop device that could make labeling easier for the visually impaired. Product could be on the market next year. A device that started out as a class project last fall is moving rapidly toward becoming a commercial product...

I have a device I need made, but I don't know if there is enough information in the patent to have an engineer create it. Here is a link to the device...

I'm doing something that requires pressing my computer's mouse button once every 15 minutes so I'm trying to find something that will automatically do it for me whether I'm there or not. If anyone has seen that Simpsons episode where Homer uses the drinking bird to press the "Y" button on his...

Homework Statement Suppose that 2 identical photoelectric devices are connected to the same electrical circuit, and the devices are connected in parallel with each other. Compared to the voltage generated by a single device, the total voltage supplied by the parallel devices will be...

Hi Guys I am new engineering and would appreciate any advice or ideas on this project. I need to measure the height above sea level of a small vehicle that I am building.. My first idea was GPS, but the vehicle is going travel under a thick steel structure, so it will not work. I thought...

I am trying to figure out how to design a stair-climbing device similar to a hand-cart that climbs stairs. I know that the loading will be ~500 lb. It uses a 3-wheel climbing design design like http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200381541_200381541" except...

Hi, time ago I found some Youtube videos and a website about this kind of device made of mirrors that invert the light coming from an object, and the effect (even if I don't remember precisely) should be to disrupt the sense of depth. This is a quickly made illustration of this device...

Homework Statement I have been asked to design a device or assemble existing devices that will measure light intensity from a source across diifferent places on a table, the data has to be recorded electronically on a computer as well, the position of the measuring point has also to be...

What is a smallest system which can be considered a 'measurement device' in terms of CI. How many atoms does it consist of?

I had a small, about 1 foot secondary tall tesla coil with about 3 inch leaders coming off the toroid, and when i turned it on, I had an LED bike blinker light that would turn on when I would turn on the tesla coil. The blinker was about a foot away from the coil. I was wondering if anyone...

Lets assume an Alien race that's 1.2 billion years ahead of human civilization in terms of technology. Do you think they'd be able to store the entire internet in one of their single device? If not, then how much storage do you think they'd have? Discuss..

Learning device, help me expound: on Faraday's choice of "ion", and "unionized" So I was writing down some notes to myself on electrochemistry (100 level college chemistry---elementary electrochemistry chapter) and I wrote down the word "unionized" (as in, 'un-ionized') and realized that there...

What are the major device ratings for a MOSFET?

Hi, I'm trying to model the frequency response of a thin PZT disc using COMSOL, but I am not sure how to calculate the impedance Z vs frequency. I defined the current density at the top electrode as I=-imag(nJ_smpz3d) and then plotted V/I using the domain plot parameters in the postproc menu...

hi I am doing my Electronics and Communication Engineering..I need a topic for paper presentation.Im more interested in semiconductor devices and device physics..It's like,i would like to address any physical limitation in the existing technology in reducing chip size.(this is the only topic i...

Is there anyone who knows of a tracking device small enough to install inside a notebook/laptop. Apart from RFID tags which only track within a given range. A GPS device that would track an asset as it were a car

Homework Statement Suppose you build a two-engine device with the exhaust energy output from one heat engine supplying the input energy for a second heat engine. We say that the two engines are running in series. Let e1 and e2 represent the efficiencies of the two engines. (a) The overall...

I was just curious what would happen if a device working at for example, 5 V DC voltage, is given 10 V peak to peak AC voltage. Would the device still operate? maybe it depends on the device but can someone briefly explain ..? thanks!

Hi Guys, :smile: I have heard of many energy saving devices available commercially, which when connected in parallel with the household mains, cause reduction in electricity bills. In smaller sizes they can be connected in parallel with any household power recepticle and cause reduction in...