Buzz buzz remover?

[RJH]

Isn't that a fashion, and the use of toroidal more a coincidence than cause of 'decent'?:

Granted, though, they don't seem to buzz IME.

[Dave Plowman (News)]

They produce a much smaller unwanted magnetic field outside of them - so very useful where this matters, like say audio equipment.

Doubt it's 'fashion'. They are more expensive, like for like. And maybe smaller/more convenient shape for packaging.

[The Natural Philosopher]

Not necessarily. Again its all down to materials and peak flux density.

The great advantage is that although winding needs a more complex machine, the cores themselves come pre made and assembled and usually epoxy dipped so there is less cost in that and no need to do E and I insertion on a bobbin and clamp the laminations up.

They aren't like for like though, and that is the point.

[Dave Plowman (News)]

In terms of the type being discussed here, I'm happy with my statement.

They always cost more to buy.

They trasform an AC voltage. Is that like for like enough for you?

[Dave Plowman (News)]

That article is written with reference to US mains. Very different from the UK. And, I'd say, by someone with a bee in his bonnet.

[The Natural Philosopher]

he has a few good points a few utter myths and some incorrect information.

[The Natural Philosopher]

No, they dont.

Not if you are busy talking about hum performance which is related to a lot of things that are not 'transforming one voltage to another'

[Dave Plowman (News)]

Plenty nonsense about mounting. Fully encapsulated versions are available if in the unlikely event there are problems mounting one.

[Dave Plowman (News)]

I'm curious to know what type of transformer has a lower external magnetic field?

[tony sayer]

In article , Dave Plowman (News) scribeth thus

Some right old twaddle but thats a very old article 1998.

Never seen anything but toriods used in the audio companies I've worked for over time such as Neve, Audix and Audiolab plus Pye TVT..

[Graham.]

I had one of these until quite recently, when it was accidentally disposed of with a load of scrap metal.

I also had one of these

[News]

In message , Graham. writes

Wonderful! That is post war, sold by Meccano Ltd for use with their Hornby Dublo range, 00 gauge, 0-12v DC. They tend not to buzz too much. I had in mind the earlier units for 0 gauge trains running on 0-20v or more AC, and it is they which can buzz alarmingly. There are still countless 1930s built units in regular use and, when PAT certified for public exhibitions, invariably pass with flying colours, the only usual attention required being a new mains lead.

[Chris Holford]

In the article he seems to imply that toroidal transformer cores are made from a pile of 'O' shaped laminations with no air gap. Is that right? I understood they were made by winding a long strip in a spiral rather like winding up a measuring tape. If the long strip is insulated on one side the there will be an air gap.

[Johnny B Good]

I believe that's how toroidal cores are made (but stampings could also work - I suspect not so well since the special steel tape can be annealed under the influence of a strong magnetic field to align the magnetic domain boundaries to maximise their efficacy as a wound magnetic core).

Whichever way you make up a toroidal core, you're still left with the knotty problem of winding the coils which requires more specialised coil winding machines[1] to thread the wire through the middle of the toroid.

The tape wound toroidal core maximises the areal flux density for a given cross section of core material and the circular magnetic flux path reduces the length, avoiding the sharp corners of the classic T & U or E & I stampings commonly used in the more traditional designs, virtually eliminating leakage flux since all of the flux is captured by the 'endless solenoid' windings (no exposed core with sharp right angled corners).

I once used such a mains transformer (60VA) as an auto transformer (split mains primary windings of 120 + 120 vac in series, making up a

240vac primary with a 120vac tap) to convert a 120v mains IBM CRT monitor, that I'd picked up at a bargain price at a radioham rally nearly 3 decades back, to 240v operation in the form of a self contained modification otherwise totally impossible using a traditional transformer.

My initial tests using a few suitable 'normal' transformers revealed that they needed to be kept a good metre or more away from the CRT to eliminate 'mains wobble'. The toroidal was so well 'self screened' I was able to shoehorn it into the monitor itself without even the slightest hint of such 'wobble' being detectable.

[1] Here are some examples of toroidal winding machines on youtube:

starting with this:

Once you've watched a few of these videos, you'll understand why they are so much more expensive than their cheap 'conventional' counterparts.

BTW, I've no idea why they seem to be employing a 'Smurf' in this video: :-)

[Johnny B Good]

====snip====

After looking at some other videos with flesh tones, it would seem that the 'smurfication' is a colour rendering issue in my web browser, Opera, running in Linux Mint 17.1. Strangely, the seek bar thumbs render ok, it's just the video rendering that seems to be lacking the red component. Yet another issue to sort out in my transition from Microsoft windows (win2k) to a Linux host OS (at the moment, just a minor one compared to the rest of the many issues I've yet to sort out with this transition).

I've just fired up FF for the first time and the videos render just fine so obviously just a problem in my version of Opera. :-(

[Bob Eager]

Right click on the image and turn off hardware acceleration. Nvidia card?

[Bob Eager]

(may need to restart the browser)

[Bob Eager]

I realise that was all a bit ambiguous. Play any video. Right click on the image while playing. Select the Settings (not Global Settings). Un- tick the 'Enable Hardware Acceleration).

Restart Opera. It's a long standing problem.

[Johnny B Good]

Thanks Bob! That did the trick. Not straight away, I had to close and restart the browser allow the change to be applied. And, yes, it's an Nvidia card, an Asus 8400GS silent I purchased for my last major hardware upgrade 5 years ago.

My current fun and games is the result of a MoBo/CPU/DIMM hardware upgrade forcing me to abandon win2k as a host OS and precipitating my long promised move to a *nix host OS (using Vbox to virtualise any windows installations as guest OSes of which I've already had some experience with over the last two or three years in various test setups).

Actually making the transition is the only way I'll properly get to grips with *nix. The test setups were on the bench behind my back so I wasn't really able to give them the attention they deserved from a "Getting to know the system" PoV.

[Johnny B Good]

Yup! Figured that one out when it didn't immediately show any change (I'm rather an old hand at this stuff :-)