Talk:Dielectric heating

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Aren't cellphones thought to be more damaging because EMR can rip electrons off DNA and other molecules, creating free radicals?

No. See ionizing radiation and non-ionizing radiation. Microwaves are non-ionizing. Jmesserly 17:40, 9 April 2006 (UTC)

Diathermancy is different from diathermy[edit]

See es:Diatermancia —Preceding unsigned comment added by Fev (talkcontribs) 00:33, 30 September 2008 (UTC) Do microwave heat food using conduction?...why or why not —Preceding unsigned comment added by (talk) 03:34, 24 October 2008 (UTC)

Heating Metal[edit]

There should be a section in this article as to why metal is not supposed to be put into microwaves. This article lacks that knowledge, and I do not have it. (talk) 20:28, 2 October 2010 (UTC)

It is not a universal rule that metal should not be put in the microwave; in fact you can find microwaves with metal racks (like a conventional oven). You shouldn't however, place metal objects with sharp points on it (e.g. fork) as it can create electrical arcs. This is already covered in the microwave oven page. (talk) 21:03, 6 January 2011 (UTC)

Microwave transmission dangers[edit]

Microwave ovens put out 1,000 watts commonly, and still the unfocused beam degrades exponentially in air, to the point that a couple meters is safe distance from an unfocused, operating magnetron. in contrast, microwave transmission antennas usually use 1 or 2 watts of power. they are focused/colliminated, and are yet still not powerful enough to cause the mentioned deep tissue burns. —Preceding unsigned comment added by (talk) 03:40, 9 February 2011 (UTC)

merge suggestion[edit]

I suggest that diathermy be merged into dielectric heating. As far as I can tell, both of them talk about the same thing -- using high-frequency electric energy to heat muscles. Since they are different names for the same thing, I think they should be in the same article -- the same way that puma and mountain lion share one article. Even if there are slight differences in how people use those terms, that difference can be discussed in the article. (Merging the other way would also be fine with me). -- (talk) 14:37, 19 July 2008 (UTC)

Article merged: See old talk-page Talk:Diathermy. —Preceding unsigned comment added by (talk) 05:15, 27 July 2008 (UTC)

I disagree. Most medical professionals see diathermy not as a generic heating of material, but as a particular tool used quite specifically to cut and cauterise living tissue. While I appreciate that the concept (mechanism of action) is more or less the same, placing a specifically medical term under a generic heading about cooking food would lead to unnecessary concerns by people who don't appreciate the difference - patients about to undergo diathermy procedures, for instance! Would it not be better to leave the diathermy page in place, with links here for mechanism of action for those interested?Cephas Borg (talk) 23:21, 4 November 2012 (UTC)

I should point out that the medical use of diathermy already has its own page, which doesn't need to be merged at all with this article. Cephas Atheos (talk) 00:27, 5 November 2012 (UTC)

Second merge suggestion[edit]

I noticed that RF heating redirects here. However, there is also an article on radio frequency heating. If anything, 'RF heating' should redirect to that page unless dielectric heating and 'RF heating' are the same thing, in which case a merge is in order.--Subversive Sound (talk) 01:57, 9 March 2010 (UTC)

I've pointed RF heating to Radio frequency heating for the moment, but I also think that Dielectric heating article ought to be merged with Radio frequency heating as it is a subset of that concept. (talk) 12:51, 24 March 2010 (UTC)
Agree with merge. --Wtshymanski (talk) 22:17, 14 November 2011 (UTC)
Agree with merge as well. The parts of radio frequency heating that are not duplicated here can be copied to here (the section of that article that talks about the generation of heating is much poorer than this one's), and that article redirected to here.

Not all dielectric heating is done at RF frequences, but almost all of it is, since it is very inefficient at lower frequences (what is the lower limit to RF anyway? 1000 Hz?). We should make the distinction that "radio frequency" does not always mean production of actual "radio waves." A radio wave is something that propagates freely through space, like the microwaves that come out of a microwave antenna, or the radio waves that come out of a radio antenna. Dielectric heating uses electromagnetic signals at RF frequencies, but the fields between the capacitor are near fields, which means they are close to being static fields with much more E than B component, and they consist of virtual photons (rather like the induction fields inside a transformer), not real photons. Thus, they are not free-space, far field "radio waves," in the classic sense. Inside a microwave oven, there really do exist EM free-space microwaves, since the wavelength is far shorter than the gap between the metal walls. However, inside the metal plates of a dielectric heater, that isn't true, so the entire effect is near-field, without production or absorption of any genuine radio waves-- even if the frequences are RF frequences. SBHarris 23:18, 14 November 2011 (UTC)

Clarification required for useless formula[edit]

The first (inline) formula in the Power section needs to be explained. Since none of the terms used are identifiable by anyone who's not some kind of RF engineering specialist, as it stands the formula is confusing and actually detracts from the rest of the article (which is otherwise rather good!). Update : added the Formula Missing Description templates (my first use of a template, so I hope it's appropriate!)

If anyone could give me a quick pointer on how best to recruit an expert, it would be very much appreciated. Thanks.Cephas Borg (talk) 22:38, 4 November 2012 (UTC)

There is a template:

But Wikipedia tends to be hard on experts for obvious reasons, so you won't find all that many here. SBHarris 02:03, 5 November 2012 (UTC)
Better now? — HHHIPPO 17:24, 11 November 2012 (UTC)

"Holds promise"?![edit]

"RF heating holds promise as a way to process foods quickly." Honestly, doesn't this sound ludicruous, in the light of this being a 70+ year old technology, and in fact predating microwave ovens by decades? This is like saying that AM radio "holds promise" of longer range, cheaper operation over FM. (talk) 14:35, 21 August 2013 (UTC)

Having trouble interpreting this apparently self-contradictory statement:

"Frequencies in the range of 10–100 MHz are necessary to cause efficient dielectric heating, although higher frequencies work equally well or better"

Which clause is the correct one? --Sigfpe (talk) 17:19, 3 December 2014 (UTC)

Intermediate frequency[edit]

Intermediate frequency normally means a local frequency in a superheterodyne receiver. Exactly what does "intermediate frequency" mean here? Is it a subset of the microwave band? Comfr (talk) 18:33, 2 January 2016 (UTC)

External links modified[edit]

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Dire need of citations[edit]

The entire section on dialectric heating has been marked as requiring citations for over three years as of June 2016, so I added a page tag. If I get some spare time I'm going to try and dig out some physics books on the subject (talk) 23:28, 18 June 2016 (UTC)

Dielectric heating in electrical insulation[edit]

Dielectric heating is also a term used to describe frequency related heating in electrical insulation used for safety or functional purpose, such as insulated wire. This can be a problem in frequencies as low as 100kHz, depending on the material. For example, PVC that is normally OK for 2.5kVac @ 50Hz can break down at 500Vac 400kHz due to dielectric heating (this voltage and frequency being commonly associated with electrosurgery). The materials in a switching transformer (bobbin former, wire) can also heat up due to switching frequencies (these days up to 200kHz). The subject is related to the Wikipedia article on Dissipation factor but this only talks about capacitors and does not describe the mechanism or the potential impact on electrical insulation. I think it makes sense to include here.