Floating differential current sources

A nice story, but then it should be the same for all coils no?

So what happens when you use capacitoes and not resistors? So say 100 pF (wild guess) on one coil, and a 20-200 pF tuning cap on the other?

(I have, for special 'tuning cases' bought a nice antique tuning cap on ebay a few years ago, here in action, connected to a SARK100 antenna analyzer and my software:

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The GNU plot of the data:

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)

Not sure I can view podcasts on this system, no but from their download link wget "

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" works, downloaded the 96 MB file... lemme see ls -rtl p1216*

-rw-r--r-- 1 root root 103079274 Dec 19 01:31 p1216.mp3?c_id\=29477762&cs_id\=29477762&expiration\=1545424571&hwt\=d04b8aeccc04c31bd76374e249bb89cb

panteltje12: ~/download/html # mv p1216* penrose_podcast1216

panteltje12: ~/download/html # mediainfo penrose_podcast1216 General Complete name : penrose_podcast1216 Format : MPEG Audio File size : 98.3 MiB Duration : 1h 47mn Overall bit rate : 128 Kbps Album : The Joe Rogan Experience Track name : #1216 - Sir Roger Penrose Performer : Joe Rogan Accompaniment : Joe Rogan Genre : Podcast Cover : Yes Cover description : Array Cover type : Cover (front) Cover MIME : image/jpg Lyrics : Sir Roger Penrose OM FRS is an English mathematical physicist, mathematician and philosopher of science. He is Emeritus Rouse Ball Professor of Mathematics in the University of Oxford and Emeritus Fellow of Wadham College, Oxford. Comment : Sir Roger Penrose OM FRS is an English mathematical physicist, mathematician and philosopher of science. He is Emeritus Rouse Ball Professor of Mathematics in the University of Oxford and Emeritus Fellow of Wadham College, Oxford.

Audio Format : MPEG Audio Format version : Version 1 Format profile : Layer 3 Duration : 1h 47mn Bit rate mode : Constant Bit rate : 128 Kbps Channel(s) : 2 channels Sampling rate : 44.1 KHz Resolution : 16 bits Stream size : 98.0 MiB (100%)

103079274 bytes for 1h 47 minutes

panteltje12: ~/download/html # mv penrose_podcast1216 penrose_podcast1216.mp3 panteltje12: ~/download/html # play penrose_podcast1216.mp3

penrose_podcast1216.mp3:

File Size: 103M Bit Rate: 128k Encoding: MPEG audio Channels: 2 @ 16-bit Samplerate: 44100Hz Album: The Joe Rogan Experience Replaygain: off Artist: Joe Rogan Duration: 01:47:03.11 Title: #1216 - Sir Roger Penrose

In:0.05% 00:00:03.53 [01:46:59.58] Out:165k [-=====|===== ] Hd:4.5 Clip:0

'ladies and gentlemen welcome to the p o d c a s t this epi...' I will listen to it later, many thanks.

Reply to
<698839253X6D445TD
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On Friday, December 21, 2018 at 1:37:17 PM UTC-5, snipped-for-privacy@nospam.org wr ote:

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Manufacturing differences is my story. We are talking very small effects less than 1 in 10^3 That could be just differences in the wire thickness as it goes down... thinner wire wraps a little tighter.

other? Capacitors do nothing. It's all at DC (at least for these coils) I sweep through the signals very slowly.. a 5-10 seconds for a trace is common. I could go as slow as I want, except you then see the effects of temperature drift (in the Rb absorption cell)

There's already a big 330 uF cap across both coils, as a Zobel network. (in series with 10 ohms)

There are some other RF coils in the system at right angles to the DC B-field. In the first picture here,

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The white thing in the middle is the Rb cell heater, on the outside you can see some circular thing.. that is one RF coil. The other is on the other side. (three turns each) The big 12" coils are what I'm tweaking with the resistor. ~400 turns a side.

One issue with the current stealer is that at higher currents (3A) the coil s get hot ~100W, which means the resistance goes up and that will screw up how much current is stolen. Coils get to maybe 60 C when run at max. current, so only ~10% effect (330 K/300 K) hopefully that won't be too much of a problem. I'll find out.

George H.

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mathematical physicist, mathematician and philosopher of science. He is Em eritus Rouse Ball Professor of Mathematics in the University of Oxford and Emeritus Fellow of Wadham College, Oxford.

mathematical physicist, mathematician and philosopher of science. He is Em eritus Rouse Ball Professor of Mathematics in the University of Oxford and Emeritus Fellow of Wadham College, Oxford.

.mp3

== ] Hd:4.5 Clip:0

Reply to
George Herold

George Herold wrote

Is it not the ratio that counts, it is a bridge, balanced, should not make much difference,

Very nice work, yes you must be right, was spacing out a bit, too much coffee with cream. :-)

How do I explain I am an alien clone.

Back to the chocolate.

NTCs PTCs thermocouples, control loops, big fan,

but but I see an ANALOG meter on that box, is that still legal? I have read people can no longer read analog clocks, how about meters?

My rubidium 10 MHz frequency reference (also from ebay) is much smaller... ?

I will ask Panteltje about it when I teleport back.

If ever.

Reply to
<698839253X6D445TD

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