Creating Electromagnetic Waves with an Electromagnet: Fact or Fiction?

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Discussion Overview

The discussion revolves around the creation of electromagnetic waves using electromagnets and the principles behind generating such waves, including the roles of capacitors and inductors. Participants explore theoretical and practical aspects of electromagnetic wave generation, including oscillation frequencies and the mechanics of radio wave production.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that moving an electromagnet can create electromagnetic waves, questioning the feasibility of generating various types of waves by adjusting the speed of movement.
  • Others argue that electromagnetic waves are generated through rapidly changing electric fields, emphasizing that radio waves result from moving electrons rather than just moving magnets.
  • A participant highlights the use of resonant circuits involving coils and capacitors to generate specific frequencies, suggesting that the inductivity and capacity determine the resonance frequency.
  • Some contributions clarify that capacitors and inductors can store energy and facilitate oscillation, but they do not directly produce radio waves; rather, they enable the conditions for electrons in a wire to oscillate and emit waves.
  • There is a discussion about the size and practicality of capacitors and inductors, with some participants expressing interest in building their own wave-generating devices.
  • One participant provides an analogy comparing the oscillation of energy in capacitors and inductors to a pendulum, explaining how resonance works in this context.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the mechanisms of electromagnetic wave generation. While some concepts are clarified, there remains uncertainty about the roles of different components and the feasibility of generating waves through various methods.

Contextual Notes

Limitations include varying levels of understanding among participants regarding electromagnetic theory, inductors, and capacitors. Some statements rely on assumptions about the participants' familiarity with the underlying physics concepts.

Who May Find This Useful

This discussion may be useful for individuals interested in electronics, electromagnetic theory, and radio wave generation, particularly those seeking to understand the principles behind these phenomena.

  • #31
is the crystal a germanium diode?
 
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  • #32
Yes, they generally sell these kits at Radio Shack. They're a great place to begin tinkering with electronics.

The radios are still called "crystal radios," even though they no longer contain a crystal. In the old days, they were built with a small crystal of lead sulfide and a bit of metal, used to allow current to pass in one direction but not in another. In a modern crystal radio, the germanium diode performs the same function, but better.

- Warren
 
  • #33
cool. ill definitely check out radio shack tomorrow
 
  • #34
does the radio create the radio waves? if it did, wouldn't that be a perpetual motion device?
 
  • #35
No... a crystal radio receives radio waves from a transmitter tower operated by the radio station. It's definitely not a perpetual motion machine!

- Warren
 
  • #36
what inductance (current range) works best for radios? should i post building a radio in the engineering section?
 
  • #37
I don't know what you mean by "current range," but the inductor used in a crystal radio is selected, along with the capacitor, to provide resonances at the appropriate transmission frequencies. More complex radios are, well, more complex.

- Warren
 
  • #38
at wilcocorp.com/catalog, you can get free inductors but it asks for an inductance range or current range.
 
  • #39
Current range is probably the current limit. Don't forget, if you pass too high of a current through a wire it will burn like a fuse or a burnt out lightbulb.
 
  • #40
what would be the ideal limit for a radio or practical for experimenting?
 

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