Author Topic: Fear of mains from 1990s  (Read 1529 times)

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Offline Raj

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Fear of mains from 1990s
« on: April 14, 2021, 11:29:10 am »
An extract from elektor issue 177 describes a circuit to protect you from electrical fields.  :-DD
 

Offline Cyberdragon

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Re: Fear of mains from 1990s
« Reply #1 on: April 15, 2021, 03:16:54 pm »
Why the hell would they publish this BS in a real tech magazine? I mean, the circuit probably does what it says but why would they touch this topic with a 10 foot pole? That only leads down rabbit holes of readers calling in and requesting all manner of bullshit electronics.

Imagine if Make or Nuts and Volts published something like this today!
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Online Twoflower

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Re: Fear of mains from 1990s
« Reply #2 on: April 15, 2021, 03:20:03 pm »
Have you checked the date of that issue? It is visible on the first page  ;)
 
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Offline ebastler

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Re: Fear of mains from 1990s
« Reply #3 on: April 18, 2021, 03:41:57 pm »
Also note the authors - Mr. Serious and Mr. True.  ;)
 
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Offline David Hess

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Re: Fear of mains from 1990s
« Reply #4 on: April 18, 2021, 09:47:36 pm »
It reminds me of the Tektronix A6901 Ground Isolation Monitor except that the A6901 serves a purpose in allowing an arguably safe floating ground:

https://w140.com/tekwiki/wiki/A6901
 

Online TimFox

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Re: Fear of mains from 1990s
« Reply #5 on: April 18, 2021, 11:15:01 pm »
QST magazine (ARRL publication for radio amateurs) had good April issues back in the day.  I remember one where the author combined a tapped inductor (Hartley circuit) with a tapped capacitor (Colpitts circuit) to form a hybrid oscillator that he called a Harpitts.  Since it was well known that one of these (I forget which) standard oscillator circuits chirped "up" when keyed, and the other chirped "down", the combination did not chirp.  In fact, it showed "electronic backlash", where the frequency change would be delayed from the rotation of the tuning variable capacitor (although this might have been due to the 1/4" ID rubber tubing used as a shaft coupling).
 
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Offline T3sl4co1l

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Re: Fear of mains from 1990s
« Reply #6 on: April 18, 2021, 11:44:22 pm »
Or the arbitrary separation distances given by Dr. Palm... :)

Interestingly, it does provide another feature (if not a very useful one for the most part): the output is largely disconnected from mains, meaning it's insensitive to common mode or unbalanced loads.  It only activates from differential load (H to N).  That might be something of a safety feature, if an incomplete one (as, once the load is engaged, this function disappears).

One of the April issues that's stuck with me, was an Electronics Now proclaiming a revolutionary new slot-type CPU (as the Pentium II was all the rage, at the time), made from gallium arsenide and alloys, which was purported to glow intense red in operation, being made from LEDs and optics, and as we all know, optical waveguides are terribly fast compared to silicon interconnects -- and equally so, GaAs is famous for producing many-GHz RF transistors.

I guess the irony is, the Cray supercomputers (old news by that time) were built with GaAs, or the ones that were, anyway.  It would be neat if someone fixed the problem with that (AFAIK, they were entirely NMOS, very power hungry indeed; due to GaAs having quite high electron mobility, but utterly pitiful hole mobility -- CMOS makes no sense whatsoever on it), and perhaps that was one of the revolutionary features developed there.

Nevermind that, as the Slot and x86 architecture were very closely held Intel patents, a 3rd party developing a complete drop-in solution for it all would be honestly the more remarkable piece of work.  One of those... practical details easily left forgotten, when reading about something so remarkable... :)

(Not that it had any practical effect on me -- as, even if I wanted to, there wasn't much a kid like me could have bought back then. ;D Judging by some of the letters published in the following issue, there were plenty of people, with means, who were more easily swayed. :-DD )

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« Last Edit: April 18, 2021, 11:53:59 pm by T3sl4co1l »
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Offline David Hess

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Re: Fear of mains from 1990s
« Reply #7 on: April 19, 2021, 10:36:22 pm »
I guess the irony is, the Cray supercomputers (old news by that time) were built with GaAs, or the ones that were, anyway.  It would be neat if someone fixed the problem with that (AFAIK, they were entirely NMOS, very power hungry indeed; due to GaAs having quite high electron mobility, but utterly pitiful hole mobility -- CMOS makes no sense whatsoever on it), and perhaps that was one of the revolutionary features developed there.

And also no native insulating oxide.
 
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Offline james_s

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Re: Fear of mains from 1990s
« Reply #8 on: April 19, 2021, 10:43:49 pm »
Gag articles in the April issue of electronics magazines is an age old tradition. I remember getting a good laugh out of the ones in Radio Electronics, and the resulting letters (some serious, some jokes themselves) that would invariably result.
 
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Offline Raj

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Re: Fear of mains from 1990s
« Reply #9 on: April 20, 2021, 06:15:01 am »
Have you checked the date of that issue? It is visible on the first page  ;)
Gag articles in the April issue of electronics magazines is an age old tradition. I remember getting a good laugh out of the ones in Radio Electronics, and the resulting letters (some serious, some jokes themselves) that would invariably result.

Now I get it...I thought they were serious :-DD Happened to post this in April too :p
 

Offline Ranayna

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Re: Fear of mains from 1990s
« Reply #10 on: April 20, 2021, 10:34:48 am »
Would have worked way better if they also translated the names of the authors. But since names are generally not translated they likley did not have a process for that.
I wonder if the translators took this seriously?
 

Offline Alex Eisenhut

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Re: Fear of mains from 1990s
« Reply #11 on: April 20, 2021, 05:50:48 pm »
Gag articles in the April issue of electronics magazines is an age old tradition. I remember getting a good laugh out of the ones in Radio Electronics, and the resulting letters (some serious, some jokes themselves) that would invariably result.

I remember an article in some electronics magazine decades ago that said they could get stereo out of a single speaker by timing which side of the cone outputs which channel of the audio... hahaha

I also recall the macrowave oven that cools food down.
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Offline SiliconWizard

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Re: Fear of mains from 1990s
« Reply #12 on: April 21, 2021, 09:41:07 pm »
And, it's always fun to see people falling for the gags while playing debunkers.
 

Offline Tens

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Re: Fear of mains from 1990s
« Reply #13 on: April 24, 2021, 08:44:32 pm »
There was a short article in an April edition of RadCom, a British radio amateurs' mag, back in the 70s. Showed a graph that could be used to look up a conversion from the old established 'cycles per second' to the new fangled 'hertz'. The cps axis was linear whilst the hertz axis was logarithmic, just to confuse things a little.
 

Offline David Hess

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Re: Fear of mains from 1990s
« Reply #14 on: April 24, 2021, 08:48:11 pm »
CPS to Hz conversion chart:
 
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Online TimFox

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Re: Fear of mains from 1990s
« Reply #15 on: April 24, 2021, 10:11:46 pm »
When the change from c/s to Hz was first proposed, a critic suggested “One may as well call the liter per minute the ‘Falstaff’.”
 

Offline Ultrapurple

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Re: Fear of mains from 1990s
« Reply #16 on: April 28, 2021, 10:59:06 am »
Also from RadCom, April 2018 this time - a rub-on coax VSWR improver:
Rubber bands bridge the gap between WD40 and duct tape.
 
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Offline vk3yedotcom

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Re: Fear of mains from 1990s
« Reply #17 on: May 09, 2021, 12:06:47 pm »
QST magazine (ARRL publication for radio amateurs) had good April issues back in the day.  I remember one where the author combined a tapped inductor (Hartley circuit) with a tapped capacitor (Colpitts circuit) to form a hybrid oscillator that he called a Harpitts.  Since it was well known that one of these (I forget which) standard oscillator circuits chirped "up" when keyed, and the other chirped "down", the combination did not chirp.  In fact, it showed "electronic backlash", where the frequency change would be delayed from the rotation of the tuning variable capacitor (although this might have been due to the 1/4" ID rubber tubing used as a shaft coupling).

And, glory be, the Harpitts article can be read here:

http://www.arrl.org/files/file/Technology/Larson%20E_%20Rapp/1956_April.pdf
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Offline Ultrapurple

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Re: Fear of mains from 1990s
« Reply #18 on: May 09, 2021, 01:03:44 pm »

And, glory be, the Harpitts article can be read here:

http://www.arrl.org/files/file/Technology/Larson%20E_%20Rapp/1956_April.pdf

Though that is clearly a spoof, it does put me in mind of the 'double tank oscillator' espoused by the late Colin Horrabin, G3SBI. See here. Great things have been claimed about the low phase noise of double tank oscillators, as will be found if you search the professional literature.
« Last Edit: May 09, 2021, 01:13:21 pm by Ultrapurple »
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Offline Ultrapurple

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Re: Fear of mains from 1990s
« Reply #19 on: May 09, 2021, 01:10:41 pm »
I also recall the macrowave oven that cools food down.

No, you're mistaken. A macrowave oven is one that uses HF  :-DD

Years ago I visited a BBC shortwave transmitting station. One of the transmitters had an output coupling coil a couple of feet diameter that was mounted on a railway bogey-type arrangement so it could be wheeled in and out to adjust the coupling for different frequencies. Sitting across the middle of the coil was a stained piece of wood that clearly wasn't part of the original design. I asked what it was, and they told me it was their patent pastie heater. Particularly in the winter months when the wind whistled through the transmitter hall, they would put Cornish pasties on the wood while running-up the transmitter into a dummy load prior to going on air. The intense field strength was more than enough to get them piping hot in a few minutes!

I also wonder whether diathermy machines count as macrowaves...?
« Last Edit: May 09, 2021, 01:15:22 pm by Ultrapurple »
Rubber bands bridge the gap between WD40 and duct tape.
 

Offline T3sl4co1l

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Re: Fear of mains from 1990s
« Reply #20 on: May 09, 2021, 04:48:02 pm »
Yup, 27MHz and a few other bands are not uncommon for diathermy, heating of food, plywood, etc. industrial uses... :)

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Online TimFox

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Re: Fear of mains from 1990s
« Reply #21 on: May 09, 2021, 10:15:13 pm »
The RCA Transmitting Tube Handbook had application schematics for an induction heater (magnetic field) and a diathermy heater (electric field).
 


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