- #1
Paper
- 14
- 1
Hello,
I'm confused about the whole electromagnet thing. So far I've got these concepts:
- Passing a current through a wire results in a magnetic field 90 degress to the direction of flow
- If the current is AC, the magnetic field is continuously alternating
- This magnetic field is considered to be a near field and can be used to perform inductive coupling
- In addition, this AC current causes the wire to radiate electromagnetic waves (radio frequency light). This is part of the far field
- If we alternate at the natural resonance frequency of a wire or coil, we set up standing waves in the transmitter
- And so the receiver needs only to be designed with the same resonance frequency, and an incoming electromagnetic wave of the correct frequency will cause resonance and standing waves in the receiver
Now my questions are:
* Is that all correct?
* What is the difference between a near field magnetic field and far field electromagnetic waves?
I'm confused about the whole electromagnet thing. So far I've got these concepts:
- Passing a current through a wire results in a magnetic field 90 degress to the direction of flow
- If the current is AC, the magnetic field is continuously alternating
- This magnetic field is considered to be a near field and can be used to perform inductive coupling
- In addition, this AC current causes the wire to radiate electromagnetic waves (radio frequency light). This is part of the far field
- If we alternate at the natural resonance frequency of a wire or coil, we set up standing waves in the transmitter
- And so the receiver needs only to be designed with the same resonance frequency, and an incoming electromagnetic wave of the correct frequency will cause resonance and standing waves in the receiver
Now my questions are:
* Is that all correct?
* What is the difference between a near field magnetic field and far field electromagnetic waves?