hey i need some circuits to make up a simple cell phone jammer.. can you help me out with it??
362051
Not certain as to what the regulations are in India, but in the U.S., operating such a device is not legal.\n\nJust build an oscillator that works roughly in the same frequency band as the frequencies assigned to cell phones in India.
665056
The basic components are:\n\nAn antenna (to "capture" the RF signal)\nA filter (LC circuit to tune to the frequency of interest)\nAn amplifier (to amplify the weak signal)\nAn FM demodulator (to downconvert and "decode" the FM signal and get back the baseband signal which is what our ears interepret as sound)\nAnother amplifer (make it variable so you can change the volume)\nA speaker\nOh, and of course the power supply (battery) to bias all the active components.\n\nI know you asked for a wiring diagram...but maybe try purchasing each of the above components seperately as modules and put the thing together... just do a google search... but congrads for trying to build an FM radio... It shouldn't be too bad... Make sure you have a bread board....
60148
Walsh codes are generated from a Hadamard matrix. Try this link:  http://mathworld.wolfram.com/WalshFunction.html\n\nFor more info on cell phone application, see page 552, Peterson, Ziemer, and Borth, "Introduction to Spread Spectrum Communications", ISBN 0-02-431623-7
217960
How about something like this?\n\nhttp://www.wifi-shootout.com/
513722
Check out Radio Shack
253421
I think Radio Shack has a kit that you make a simple radio i think  it's called a crystal radio. EAsy to build and good project.
185692
www.electronicsforyou.com \nor go to www.howstuffworks.com
317868
well for my physics project for the boards i made a photoelectronic burglar alarm- at the heart of this was an LDR( Light Dependent Resistor) when the beam of light is obstructed (think laser in the movies-lol) the LDR resistance rises and the circuit inside is set into oscillation and the alarm sounds- other good projects would be a rain alarm, a rectifier, an electroscope,..... the possiblities are endless- i suppose you could do anything involving electric circuits since thats what the cbse calss 12 physics text covers most- i doubt ud want to do anything on ray or wave optics
722406
Short of sheilding the building to prevent reception, their is little legally you can do. Illegally, it is easy to jam cell phones, but it can land you in trouble with the law.
914928
Google it - \n\nhttp://www.google.co.uk/search?hl=en&q=lg+monitor+circuit+diagram&meta=
191766
Have you thought of looking into Radio Shack...they have just about anything....good luck!
405936
signal converter, try tigerdirect.com great choices and prices. Plz vote for best answer I need the points,LOL
655445
check your book probably they have a website listed around.\nor visit \n\nhttp://www.siorphila.com/siorphila/resources/sixfunctions.cfm
649390
If you have a device that is sensitive to the frequencies used by cellular phones, then, yes, you can detect them with some degree of accuracy, as long as the phone is on.\n\nTry a device like http://www.globalgadgetuk.com/detector.htm, or do a search for cell phone detector (I'm not sure how legal these are in the US). They'll also give you some cell phone jammers, although jammers are illegal in the USA
121814
are you talking about the car alarm system? if so, i  installed one in my mustang and it was very basic. you should be able to go to their web site and download the schematic there.
138256
Try the Bell And Howell Website. I think you mau need to email them since the machine is so old. \n\nwww.bellhowell.com/
1070331
try www.switchboard.com - i'm not sure it will work on a cell phone though.