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-   -   How to create a eletromagnetic field with frequency? (http://www.physicsforums.com/showthread.php?t=669808)

mitocondrio Feb6-13 09:19 AM

How to create a eletromagnetic field with frequency?
 
Let's say I wanna create an eletromagnetic field with a 13.56Mhz frequency... How do I proceed it with a circuit? I don't need a large explanation, but please tell me how do I learn about it. Thanks :)

berkeman Feb6-13 10:39 AM

Re: How to create a eletromagnetic field with frequency?
 
Quote:

Quote by mitocondrio (Post 4259414)
Let's say I wanna create an eletromagnetic field with a 13.56Mhz frequency... How do I proceed it with a circuit? I don't need a large explanation, but please tell me how do I learn about it. Thanks :)

What is the overall goal? What do you want to do with this EM radiation?

mitocondrio Feb6-13 11:01 AM

Re: How to create a eletromagnetic field with frequency?
 
I want to do some RFID emulation, but I would like to learn how to create this frequency. I already learned the modulation part. I want to learn by parts. I will thank you so much if you can help me!

berkeman Feb6-13 11:05 AM

Re: How to create a eletromagnetic field with frequency?
 
Quote:

Quote by mitocondrio (Post 4259521)
I want to do some RFID emulation, but I would like to learn how to create this frequency. I already learned the modulation part. I want to learn by parts. I will thank you so much if you can help me!

What country are you in? What government agency controls the RF spectrum there? How much power are you allowed to transmit in that band, and what are the regulations on harmonics of the fundamental transmit frequency?

Is this a school project? Or for work or for a personal project?

mitocondrio Feb6-13 11:23 AM

Re: How to create a eletromagnetic field with frequency?
 
I'm studying RFIDs and how they work. I would try to do an RFID emulator just to learn better how things work. It's nothing under the government specifications, I will just use this to emulate an RFID tag for like 10 centimeters away form the reader. The tags I want to emulate uses the 13.56Mhz frequency, wich is the frequency I wanted to create with a coil.

Thanks!

berkeman Feb6-13 11:28 AM

Re: How to create a eletromagnetic field with frequency?
 
Quote:

Quote by mitocondrio (Post 4259546)
I'm studying RFIDs and how they work. I would try to do an RFID emulator just to learn better how things work. It's nothing under the government specifications, I will just use this to emulate an RFID tag for like 10 centimeters away form the reader. The tags I want to emulate uses the 13.56Mhz frequency, wich is the frequency I wanted to create with a coil.

Thanks!

The issue is that any time you transmit RF signals, you are interacting with other receivers in your area. So if you make a bad transmitter, or transmit too much power, you can cause harmful interference with other radio receivers, which is a bad thing.

The easiest way for you to do this is to use a signal generator that can go up to your frequency. Do you have access to signal generators and oscilloscopes?

mitocondrio Feb6-13 12:22 PM

Re: How to create a eletromagnetic field with frequency?
 
I don;t have an osciloscope, I would like to know how to build a circuit that can generate the signal. Could you help me? Thank you :)

Khashishi Feb6-13 01:20 PM

Re: How to create a eletromagnetic field with frequency?
 
Search google for "rf oscillator" and you get a bunch of links. For example,
www.sm0vpo.com/blocks/osc7m00.htm
There's the circuit right there. Then you just need to attach some kind of antenna.

sophiecentaur Feb7-13 12:56 PM

Re: How to create a eletromagnetic field with frequency?
 
Quote:

Quote by mitocondrio (Post 4259591)
I don;t have an osciloscope, I would like to know how to build a circuit that can generate the signal. Could you help me? Thank you :)

I assume that you have very little experience of electronics and virtually no test equipment. If this is the case then I suggest that you are heading for failure if you leap into this project so ill equipped. How would you know your circuit was working once you turned it on?

ZapperZ Feb7-13 01:09 PM

Re: How to create a eletromagnetic field with frequency?
 
Quote:

Quote by mitocondrio (Post 4259591)
I don;t have an osciloscope, I would like to know how to build a circuit that can generate the signal. Could you help me? Thank you :)

Silly question. If you don't have any ability to measure the signal generated, how in the world are you going to know you've generated such a signal?

{scratching head}

It appears that from reading this thread, you haven't thought of things through enough.

Zz.


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