I don't understand why you have spent 18 months working to design something which utilizes obsolete transformers

---Emphasis Added---

It's down to what hobbyists are willing to spend --- Equivalent contemporary ferrite transformers (i.e. units featuring floating secondaries insulated for continuous operation at 50kV+ and capable of several tens of milliamperes) 'start' at $2500 ($4k representing a 'mean' at last 'check')...
It is my observation that many are unwilling to commit such outlay to casual experimentation - especially in view of the fact that several units will likely be 'sacrificed upon the alter of (even educated) trial and error' in the course of system development...

@#12 (and just everyone) please understand that among our primary motivations with this effort is a desire to lend some integrity (dare I say dignity?) to the subject of EHT research (in contrast to the over-qualitative --often straight up erroneous-- 'three-ring-circus' that the majority of web based resources have made of the topic) --- Garnering the attention of (potentially) interested parties is sufficiently complicated by our necessary insistence upon a prerequisite bare modicum of scientific/mathematical talent -- No need to further 'alienate' our 'prospects' with insistence upon what many may reasonably consider 'expensive' parts...

I don't understand why you have spent 18 months

'Fraid ya got me there

Very best regards
HP

PS:

OMG! The sky is falling?

That's as may be - Howbeit when and if it does - the JPL assures us that its name will not be "2017 DQ36"

 

It's down to what hobbyists are willing to spend

There is my doubt. Are HV transformers for CRTs still being manufactured?
A cost of $100 is way better than $1000, but CRT TVs are waning faster than Donald Trumps' hair line.
How long do you think those transformers will be easily acquired?

 

How long do you think those transformers will be easily acquired?

Interestingly, the LOPTs best suited to general purpose EHT PSU construction (i.e. those featuring > 30kVp secondaries sans internal semiconductors, caps, etc...) were obsolete by the mid 1970's -- and yet remain available as NOS by the pallet (literally) -- As it stands, highly desirable units may commonly be had in single or small quantities for as little as $20 apiece and for Ca. 1/3'rd their weight in Cu in bulk...

Seems the NOS 'AC' LOPT market is 'blessed' by a level of interest preclusive of scraping of stock yet insufficient to rapidly deplete same -- said interest (IMO) owing, for the most part, to 'retro' home entertainment equipment enthusiasts...

Best regards
HP

 

(and just everyone) please understand that among our primary motivations with this effort is a desire to lend some integrity (dare I say dignity?)

May I add my praise to #12's your two are doing a bang-up job of it.

 

@shortbus @#12 et al...

While discussion of any topic apparent on this thread (or even remotely related to the central topic) is welcome, please note that the 'content that counts' (i.e. those areas most in need of feedback) are as follows:

-The Tutorial{s} currently post #723
-The Instrument Addendum
-My blog in general
-Subjects directly related to tutorial development (e.g. determination of essential vs. nonessential instrumentation/materials, etc)

Additionally, I ask you to please consider the fact that several seemingly 'off topic exchanges' (in regards to, for example: Aleph's original swept-spectrum CT imaging system, backscatter analyzer and fusor designs -and- JC's Captus modules and ion motion experiments) while peripheral to tutorial development are, nonetheless, spot on topic as regards EHT/particle physics/radiography/radiology application and research... and, hence, very likely of interest to the 'target' readership...

As regards the truly off-topic content - again I remind you that this thread is merely a 'work room' (as it were) and, as such, tends to be rather 'messy' - it's the finished product that counts -- I don't know how else to say it

Very best regards and many thanks!
HP

 

HP Sry cuz I have question that's a little off topic but at least it's electronics related not just personal stuff.

So do you know of way to remove phosphor from wall of like F15T8 florescent tube w/o damaging tube? HP I definitely don't want to take tube apart cuz getting fill gas and pressure right again would be a PITA! So I don't care abt phosphor staying in tube as just loose dust cuz that can be shaken or centrifuged to one end of tube once it's loose from walls.

HP You don't have to tell me doing that will NOT make it a UVC tube cuz of UV opaque envelope! I also know that if I want a clear tube I can just buy UVC tube like FG15T8! But whole point is to have a clear LP Hg arc tube that's naked eye safe!

HP just so you know I'm back experimenting with resonant Royer circuits so wish me luck!

 

Isn't/doesn't the phosphor get bonded to the tube wall in the first few seconds of life of the tube? Seems to me I saw an episode of "How its Made" that showed them lighting the finished tubes on the assembly line to bond the phosphor. Done by the phosphor reacting with the mercury drop put in the tube before evacuating and sealing it. I do know it takes quite a bit of friction on a open tube to remove the phosphor coating. I have tried it and you never get all of it off.

 

So do you know of way to remove phosphor from wall of like F15T8 florescent tube w/o damaging tube?

I've a few thoughts on that -- Please start with this:
Try an 'Excel Ultra III' (The following with reference to said instrument's 'Ultra Sound' feature) on 'continuous' at full output - couple the US applicator to the tube envelope via an excess of gel -- under no circumstances permit applicator to glass contact! Try each frequency (i.e. 1 Mhz and 3 Mhz) for best (if any) results...
Note: I advise placement of the tube under a hood (as it may implode) on a resilient, preferably highly elastic material -or- suspended via elastic bands or soft rubber grommets (so as not to 'damp' the acoustic energy)...

Please advise me of your results

HP just so you know I'm back experimenting with resonant Royer circuits so wish me luck!

You don't need luck - merely conscientious 'original research' -- But firstly I suggest you try another transformer -- Where reality/nature is concerned it cannot be "one law for Aleph and another for HP"

Isn't/doesn't the phosphor get bonded to the tube wall in the first few seconds of life of the tube? Seems to me I saw an episode of "How its Made" that showed them lighting the finished tubes on the assembly line to bond the phosphor. Done by the phosphor reacting with the mercury drop put in the tube before evacuating and sealing it. I do know it takes quite a bit of friction on a open tube to remove the phosphor coating. I have tried it and you never get all of it off.

Thank's @shortbus! -- I'm uncertain as to the bonding process - howbeit, in my experience (with reference to 'new-ish' 'Cool-White' lamps) the phosphor appears to be 'baked' on to the glass - Said bond while, IMO, on the 'tenuous side' being notably more substantial than the phosphor-to-faceplate bond encountered in monochrome CRTs...

@Aleph(0) --- Pursuant to @shortbus' observation (and my fleeting recollection) --- I suggest that the glass to phosphor bond strength may be directly proportional to the lamp's operational 'age'

Very best regards -- and, again please keep us posted!
HP

 

@Hypatia's Protege and @Aleph(0) and y'all

So Aleph asked me to post this here so everyone may know it'll be another week or so b4 she can return to regular activity here but since HP is doing the glossary it should all come right even w/o Aleph's always indispensable contribution (major sarcasm)

HP I hope you're cool with my new sig b/c you have appreciation for classic litt and for me it's totally inspired by you!

@Aleph(0) My suggestion for nondestructive stripping of fluro phosphor is to first try centrifuging as the means of loosening the powder! You know 40,000 RPM will pull a lot of Gs! I like HP's idea of giving it the old "Newton's Cradle Chaser" with ultrasound too! So I'm just suggesting centrifuging for the benefit of ppl who don't have access to US treatment equipment

So anyway sry to post and run. I should have more time now and HP I want you to know that Aleph is wrong abt my being "afraid" of you! It's just that the damage to my TC secondary was totally my fault and if I had told you abt it at the time you might have thought I was hinting for a free replacement! HP you know that would be devastating to me b/c even if some of my feelings for you are inappropriate and stupid (which I own) I need you to know I'm absolutely sincere! So anyway I'm glad to be active on AAC again

PS @Hypatia's Protege I hope I've the paragraphy format right? I'm templating with your and aleph's posts so definitely let me know if there are any problems!

 

So Aleph asked me to post this here so everyone may know it'll be another week or so b4 she can return to regular activity here

I'm so pleased you advised us of that! I'm certain the vast majority of the fora were laying awake nights wondering what became of @Aleph(0)

it should all come right even w/o Aleph's always indispensable contribution (major sarcasm)

Say what!?!?! -- 'Pots and Kettles', 'Glass Houses' --- I dunno where to begin

HP I hope you're cool with my new sig b/c you have appreciation for classic litt and for me it's totally inspired by you!

---Emphasis Added---

Um... You may wish to 'brush up' on your Arthurian Legend -- What you're saying is that I am endeavoring to (duplicitously) acquire your powers of sorcery such that I may entomb you for eternity by way of punishment for your behaviour as an elderly lecher?! -- Clearly, 'elderly lecher' doesn't fit you! - You're not old enough

My suggestion for nondestructive stripping of fluro phosphor is to first try centrifuging as the means of loosening the powder! You know 40,000 RPM will pull a lot of Gs!

'Twould be but a 'pittance' by comparison with forces attending the rapidly oscillating glass substrate via the 'ultrasonic route'

I like HP's idea of giving it the old "Newton's Cradle Chaser" with ultrasound

Thus it seems you do apprehend the underlying principle (NPI)

So I'm just suggesting centrifuging for the benefit of ppl who don't have access to US treatment equipment

---Emphasis added---

That being the case -- I assert that anyone can afford an ultrasonic humidifier (≈$40 USD) -- which being less versatile but significantly more powerful than the 'Excel')... As regards your suggestion of a 'kludged' centrifuge - please tell me you're not suggesting affixing the lamp to a prop vane?! -- Gawd! - I can hear Aleph now!!!

It's just that the damage to my TC secondary was totally my fault and if I had told you abt it at the time you might have thought I was hinting for a free replacement!

First off I know you are not -and never have been- a 'hint dropper' -- Secondly, life is far too short to permit of petty pride and 'standing upon ceremony' -- To wit: When you need help, ASK!

So anyway I'm glad to be active on AAC again

Well hey! It's nice to see you here again -- For my part I'm wondering how much longer AAC will expand to "All About Circuits" as opposed to "All About Candidates", "All About Controversy" or, merely, "All About Contention"

Best regards
HP

 

@Aleph(0)

When you get a chance, please consider uploading images of your Hg diffusion pump{s} to this thread -- Such may provide our reader's with some (hopefully) 'interesting' scientific content whilst we are at work on the tutorial 'behind the scenes'

Best regards
HP

 

Dear Aleph! More IECD difficulties and even worse public relations...

Aleph's lab marked with the fireball


TTFN
HP

 

HP Sry cuz I don't have much time right now but tbh I think tutorial is just a big waste of time! HP the problem is that the ppl who need it most are too lazy and YES! STUPID! To give a rat's a$$ abt anything more than like you say 'recipes' for sparks! (NOW I WANT EVERYONE TO KNOW MY NEGATIVE ASSESSMENT IS *NOT* OF ANY OF THE AAC MEMBERSHIP!)

HP to see what I'm talking about I say plz just look around web on subject of HV! As just minor example look on how every diagram of single bjt blocking oscillator flyback driver (which is circuit you call _half-royer_) is drawn with incorrect FB phasing which I say is a case of _numpty see numpty do_ cuz they're too lame to think through circuit for themselves so they just copy another idiot's copy of still another idiot's copy!
Also 99% of them don't know significance of arc strike length vs. draw length or how to read a schematic or even the difference between ionizing and non-ionizing radiation! HP as if all that isn't bad enough current trend is to just connect electronic floro ballast to flyback as driver like it's good design or something
HP I'm sry but I have better things to do with my life than reach out to anti-intellectual rabble! I say conceptual approach for elective losers is just casting pearls b4 swine and I'm not doing it!

HP I totally agree that ignorance in and of itself is not stupidity it's just needing to learn which is how everyone starts out with any area of knowledge! But I also totally agree that willful ignorance is totally subhuman! So I wash my hands their tawdry ranks! So if you're just saying I'm copping out don't bother! But if you really believe I missed something then I'm willing to discuss it!

Now I am saying it again cuz I mean it! NEGATIVE REMARKS DO *NOT* APPLY TO *ANYONE* I'VE SEEN ON AAC!!!

 

if you really believe I missed something then I'm willing to discuss it!

Well indeed you have! To wit: "The flowers that grow between"

Backatcha later! -- It's Saturday night!

With profound apologies to HW Longfellow
HP

PS sincerely pleased with your return! Things are pretty dull 'round here without you, gal!

 

Well indeed you have! To wit: "The flowers that grow between"

HP I say drawing parallel between earnest readers and collateral damage of grim reaper is totally bizarre

So anyway I see you are saying your 3% rule again which, IIRC, goes like _if we reach the concept driven 3% then we're 100% successful_ HP I get it but I'm saying it's more like 0.3%

HP I'm sry cuz it's going to be awhile b4 I can be back here on a regular basis (maybe not b4 2'nd week in may) so in meantime you can finish balanced HV meter and glossary entrys and we can be all set to move on to next level when I return!

So HP you'll burn me in effigy for asking silly entertainment question on here but what the hey! If you don't know maybe someone else will!

Hi @#12 I'm tagging you on here cuz you saw that I was confusing Uradhura and Uhura so maybe you know old time movies too?

So in the movie a woman lives in a brownstone Apt in NYC so I remember she has totally warped neighbors that she later finds out were like homicidal psychopaths that supposedly died years earlier. Anyhow there's one scene where she hears sounds from the Apt above hers and when she investigates she sees man who looks like victim of advanced disfiguring ARS! Anywho I saw that when I was like 6 YOA and it scared the bejesus out of me! Now I'm total vintage thriller junkie so I'd like to see movie again but even IMDB can't ID it for me cuz of too little info

So here's all I can add:
One of lead's spectral neighbors was portrayed by Burgess Meredith (or someone who looked like him) and character always brought his pet cat and a canary with him (until former partially ate latter)

I also remember priest who looked like Murry character from classic sitcom _Archy Bunkers Place_ (Martin Balsam?) Also I have feeling movie was inspired by The Exorcist (cuz of same vintage, Catholic themes and general atmosphere) but like 1000 times scarier and better than The Exorcist which was pretty lame

HP I know you're familiar with movie cuz I watched it on one of your OTM VHS cassettes b4 all transcribed to CD So anyhow I hope you can help cuz I need some real entertainment this weekend!

 

So anyway I see you are saying your 3% rule again

Correct!

so in meantime you can finish balanced HV meter and glossary entrys

So in the movie a woman lives in a brownstone Apt in NYC so I remember she has totally warped neighbors that she later finds out were like homicidal psychopaths that supposedly died years earlier. Anyhow there's one scene where she hears sounds from the Apt above hers and when she investigates she sees man who looks like victim of advanced disfiguring ARS!

One of lead's spectral neighbors was portrayed by Burgess Meredith

That'd be The original version of The Sentinel -- An excellent film, BTW

cuz I need some real entertainment this weekend

Well I can imagine your requirement of serious R&R following your week-long lark-fests

Best regards
HP

 

LOPT preparation tutorial development

---THROUGH STEP 2-11 ----


Last Action: Updated and added expansion/glossary links 6 April 2017 -- 7:40 UTC

====Introduction====

Scope of series:

Central topics:
This tutorial is one in a (prospective) series with focus upon low ripple, medium current/power PSU solutions for radiography and other modest photon energy (≤ 2 MeV) particle accelerator applications - and, to a lesser extent, exploration of certain 'current intensive' electrostatic phenomena (e.g. electret photography, electret formation, electrokinesis, establishment of electrostatically 'cordoned' (atmospheric) pressure gradients, high volume ion-flow systems, etc...

Peripheral and extraneous topics:
While everyone is welcome to view and post questions (within the confines of this site's TOS/UA) - Please be advised that those having interests confined to the following topics/applications will not likely find this series particularly useful (owing to the availability of significantly less 'labor-intensive' solutions to same):

--'Pedestrian' and 'Quasi'/'Peri'-EHT applications:
(e.g. CRTs, PMTs/Image tubes, Gas discharge devices, lasers, ionization air purifiers, TC primary drivers, GM tubes, etc...)
--Low current demonstration topics (e.g. 'Lifters', 'Jacob's Ladders', 'Plasma Spheres', 'Kirlian photography', 'Ion Motors', etc...)
--Capacitor discharge demonstration: (e.g. 'Quarter Shrinkers'/'Can Crushers', 'Rail/Coil Guns', 'EMP generators', electrical weapons, etc...)

Please be advised that site policy prohibits my assistance with most inquiries coming under the latter category...
=================================================

Scope of this tutorial
Provision of a detailed, 'step by step' procedure for modification of 'heavy duty'
AC LOPTs for 'serious' EHT application/research...

Said procedure having the following principal goals:
-- Improvement of insulation integrity via removal of auxiliary windings coaxial to the EHT winding.
-- Enhancement of versatility via electrical 'floating' of the EHT winding.
-- Appropriate adjustment of reluctance gaps.


The desirability of LOPTs:
Of the commonly available magnetic components applicable to low through medium power EHT production, the LOPT offers the advantages of relatively high power intermittent operation (several hundred to >1kW per transformer) and useful continuous power operation (to Ca. 600 Watts each transformer under forced air cooling). Moreover, LOPTs' amenability to resonant (and, hence, sinusoidal) drive permits development of systems productive of highly desirable mean output EMFs (≈70% peak) as opposed to the rather low (< 1% through 5% 'spike' EMF) characteristic of flyback and similar pulse driven/energy storage topologies. Additionally, the inherent output symmetry attending resonant drive topologies facilitates implementation of effective external EMF 'multiplication' schemes.

Prominent among the LOPT's disadvantages are the common expedient of integral rectification/EMF multiplication circuitry and 'end point' grounding schemes --- While the former objection is readily addressed via judicious transformer selection, the latter requires minor 'reconstruction' - said procedure being the subject of this tutorial.

A few words regarding the unsuitability of DSTs and their ilk:
Principally:
1) Integral components electrically unsuited to general application.
2) Practical impossibility of modification for improved EHT winding to core insulation.

Re: point 1 (above) Although asymmetrical drive may permit peak forward (and hence output) EMFs well in excess of the internal rectifiers' PIVs - such is, of course, inapplicable to 'filtered' or otherwise capacitively loaded schemes sans additional external rectifiers - moreover, internal rectification greatly complicates cascading of multiple LOPTs for increased EMF and/or development of balanced output schemes...

Re: Point 2 (above)
'DC' LOPTs are constructed as indivisible units sans 'margin' for modification -- moreover (in the case of DSTs) the rectifiers are 'distributed' throughout the winding...

LOPT Selection:
The most desirable transformers are those intended for direct production of full (AC) EHT potential for application to external 'non-multiplicative' rectification pursuant to development of accelerating potentials for large CRTs -- Contrary to 'conventional wisdom' such units are yet readily available from long-established electronics supply houses (whom, in my experience, are only too happy to wave 'minimum purchase' and 'wholesale only' policies at the prospect of disposal of what they regard as 'dead stock') --- That said, one should expect to size their purchase so as to offset the supplier's 'invoicing costs'... Prices ranging from $20 (USD) per transformer (in reasonable quantities) are not uncommon...

The following images are offered as an aid to recognition of the desired form factor:

Assorted LOPTs typical of the desired geometry:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Detail - Axial view:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Detail - Transverse view:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

The modification procedure:
--Please do not commence disassembly of the transformer prior to reading and comprehension of the entire tutorial...

Required materials:
Note: the quantities/dimensions cited below represent those necessary for completion of the modification - Minimum purchase requirements (while reasonable) will, in most cases, be significantly greater...

⇒Acetone -- QTY: 946ml ‘tin’
⇒Acrylic based hot-melt compound – Example: Surebonder Acrylstik - QTY: 100g
⇒CPVC tubing (3/4” Nom. id {CTS}) --- QTY 120mm (lineal)
⇒Elastic bands (latex) --- QTY ≈ 40g assorted sizes (≈20mm -- ≈70mm unloaded diameter)
⇒Electronics grade RTV Silicone -- Example: GC 19-155 – QTY: 90 ml
⇒Polyolefin heat shrink sleeves (3/4" untreated id) -- Example: Gardner Bender HST-750 – QTY: Three untreated 4” {102mm} sleeves
⇒Polypropylene pharmaceutical vial ( ~33mm Dia, ~64mm Len.)
⇒PTFE sheet stock – Example: http://www.eplastics.com/Plastic/ptfe_sheet -- QTY: 100mm x 60mm rectangle of 0.093” {2.35mm} stock and 40mm x 20mm rectangle of 0.015” {0.381mm} stock

Hardware:
#4 solder lug (‘inside-tooth’ fastener surface)
#4 { ≈7/64” ≈3mm} bit
#4 nut and bolt
#6 {0.83mm} burr or bit

Recommended implements:
Note 1: The reader is assumed to be in possession of standard electronics/basic ‘hand’ - tools...
Note 2: The reader is advised that 'workarounds'/'alternates' are possible for the following - please let us know should you have any questions...

⇒Dremel Moto-Tool or Equivalent
⇒Locking forceps
⇒Micrometer (Vernier) Range = 0-25mm / Res=1um {metric} -OR- Range = 0-1" / Res= 1/10,000" {imperial}
⇒Nitrile Exam Gloves
⇒Scalpels or 'X-ACTO' set
⇒Sims Uterine Curette (#3 sharp, fenestrated) -- Example: Sklar 90-5423
⇒Stainless Picks (non-magnetic)
⇒Tweezers (‘splinter’)
⇒Welder's Gloves (Supple varieties preferred for maximum dexterity)


=== Part 1 -- Disassembly of the LOPT unit ===


Step 1-1) Identify construction style of LOPT to be optimized.

Task:
1) Identify construction style via the description most closely matching the reader's device in the following...

Full EMF AC LOPTs feature one of two general construction styles as outlined below:

Style 1) Features a single piece frame ('clamp') -- the rails of which maintain compression on the core via a single linear ligature fashioned of a metallic strap or bolt extending from frame rail to frame rail across the top of the upper form leg 'facet' or 'furrow'.

Example of style 1
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Style 2) Features two independent metallic frame pieces OR a metallic half-frame and a backing plate/board -- such assemblies are bound by a single "U- bolt"/"U-strap" or two linear bolts/straps extending along the outer aspects of each horizontal form leg...

Examples of style 2

View of LOPT from 'closed' side of "U-bolt" ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

View of LOPT from 'open' side of "U-bolt" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

View of LOPT from 'closed' side of "U-strap" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

View of LOPT from 'open' side of "U-strap" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 1-2) Removal of form frame ('clamp')

Tasks:
1) Remove any tape, looped conductors, ground leads, etc. ensnaring/bonding the frame to the form.

2) Free each end of the frame ligature{s}

3A) In the case of cylindrical bolt{s} or a cylindrical shaft 'U-Bolt':
Remove backing fasteners (i.e. nut{s}/burs{s},etc...) then carefully withdraw the bolt{s} from the assembly.

3B) In the case of independent strap{s}, or a 'U-Strap': Straighten and/or unsolder each fastening 'tab' then splay the frame rails such that the frame 'ears' clear the ligature 'tabs' --Or-- if so constructed, remove the backing plate/PCB from the ligature ends ('tabs').

4) Remove the transformer (i.e. form and winding assembly) from the framing/clamping/mounting components -- please retain the frame and all associated hardware!

Image of transformer following removal from a single strap-ligature frame:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Annotated image of assembly features referenced in following steps:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 1-3) Procedure for removal of strap ligature{s} from LOPT core/winding assembly:

Tasks
1) Meticulously straighten and deburr exposed segments of the frame ligature{s}.

2) Carefully 'work' the frame ligature{s} free of the adhesive, then withdraw it/them from the space intervening the form and winding (and, hence, from the assembly) -- Under no circumstances apply counter-thrust or torque to the EHT winding!

Ligature partially withdrawn from assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Ligature (in foreground) fully withdrawn from assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Note: Inasmuch as same will be removed and discarded in later steps, damage to the external auxiliary windings (i.e. those on the form leg opposite the EHT winding) or coaxial auxiliary windings immediately adjacent to the core/form leg is of no consequence -- Care must be exercised, however, to avoid damage to the brittle ferrite form/core via excessive force or mechanical shock... Also - avoid handling the assembly by the EHT winding!

Step 1-4) Removal of external auxiliary windings from 'lower leg':

Tasks:
1) Using an appropriate scalpel, 'X-Acto knife' or similar implement, linearly section the full length of the external Aux winding assembly. --- Again, the referenced winding resides on the form leg opposite that carrying the EHT winding!!!

2) Peel, crumble and/or break the 'external' Aux winding assembly off of the lower form leg.

Step 1-5) Separation of form pieces

Caution: In performance of the following tasks, it is of paramount importance that neither torques nor linear forces are applied to the EHT tyre! -- Moderate forces may be applied to the auxiliary shell and moderate compressive force may be applied to the ferrite form longitudinal to the EHT winding 'leg' only!

Tasks:

Please note that task #1 is with reference structures coaxial to the EHT winding

1) Endeavor to remove (or loosen) any shims intervening the form and inside surface of the auxiliary sleeve -- While damage to the auxiliary sleeve or winding is of no consequence, care must, nonetheless, be exercised to avoid breakage of the form!

Image of wooden shims (indicated by pick)
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

2) Using a #3 sharp fenestrated uterine curette, or similar non-ferromagnetic stainless steel instrument, carefully 'clean' the lower form leg of superfluous epoxy -- Note: Use of razor blades or other ferromagnetic or 'soft' metallic instruments will likely 'foul' the ferrite via metallic transfer to same!

3) Submerge the lower leg of the form (prepared as per task #2 above) in acetone for a period of ≈ 90 minutes at 7°C (45°F) through 33°C (90°F) - Note: the EHT winding assembly must not be submerged, splashed or otherwise wetted with acetone! - nor should acetone be allowed to condense on same! Owing to the flammability of ketones, said procedure is best preformed in open air or in an open container 'under' an OSHA (or jurisdiction-equivalent authority) certified fume hood (caution! - this does not include 'range-hoods', 'range fireplaces', 'walk-in fireplaces' or their ilk!) -- Moreover, a closed container is not recommended owing to liability to condensation...

4) Upon removal of the lower form leg from the acetone bath, drive the reluctance spacer out of the lower form joint using an appropriate feeler gauge leaf --- Note that during and following removal of the reluctance spacer/adhesive from the lower form joint, application of even moderate constrictive or distensive forces to the form will result in significant cantilevered forces at the upper form joint with (almost certain) breakage of one or both form pieces.

Of special concern in this regard:
A) Do not attempt to expand the gap while removing the spacer! -- The leaf thickness must be less than the gap width. Maintenance of a parallel relationship between leaf and form piece ends (i.e. gap 'walls') is imperative!

B) Following removal of the spacer, take care to avoid application of constrictive/distensive forces or piece-to-piece torsion to the form! -- The safest handling method is manipulation of the assembly from one 'side' (i.e. by one form piece) only!

Note: Following clearance of the lower form joint of its reluctance spacer and adhesive, continued half-to-half form tenure owes to the upper form joint adhesive (at the center of the EHT winding assembly) - and, to lesser extent, adhesion of each form piece to the form sleeve of said assembly.

5) Using a 'heat gun', play a stream of hot (≈200°C /400°F) air in a swiftly alternating, sweeping pattern upon each 'form rail' taking great care to avoid directing said stream upon the EHT winding tyre! - In this fashion gradually and evenly increase the temperature of each 'rail' to ≈ 100°C / 200°F.

6) Wearing "welder's gloves" grasp form rails (each to a hand) then apply torque (not to exceed 5.5 N⋅cm!) axial to the upper form leg.

A) If/when form-rail to form-rail angular motion is evident, continue rotation until the pieces rotate freely relative to each other -- If necessary, the form sleeve may be used as a 'counter torque' but under no circumstances apply force of any kind to the EHT tyre!

B) In the event that relative angular motion/displacement is not discernible following 30 seconds' application of torque, repeat Task #5 (above) but heat the rails to ≈ 150°C /260°F then promptly repeat task #6 (above).

c) In the event that, having begun to move, sustained rotation becomes impossible prior to 'defeat' of the adhesive, repeat steps 5 and 6 (above) exactly as presented.

7) Carefully 'work' each form piece free of the form sleeve -- Again, avoid application of thrust or torque to the EHT winding tyre!

8) Thoroughly clean the form pieces of adhesive residue via 30 minute's immersion in acetone followed by scrubbing with an acetone wetted cotton cloth.


=== Part 2 -- modification and reassembly of LOPT unit ===

Here we will consider four (coaxial) features of the EHT winding assembly:

To Wit:
(Peripheral to central).
1) The EHT 'tyre' (comprised of the EHT winding proper, potting material and bunting).
2) The Auxiliary shell (a paperboard or polymer 'collar' intervening the central aspect of the EHT winding and the peripheral aspect of the Aux winding...
3) The Aux Winding{s}.
4) The form sleeve (intervening the central aspect of the Aux winding and the ferrite form).

Please note said features in the image below:

Image of unmodified EHT winding assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-1) Locate the lug carrying the EHT return:
The EHT return generally emerges with one or more AUX leads from the peripheral circumference of the AUX winding whence they are tied to a shell lug...

In the case of the demonstration transformer, said lug occupies the 2-o'clock postilion -- The image below shows said leads emerging from the Aux winding immediately below the CCW edge of the lug (as indicated by the ball-point pen) -- of special significance is the extreme peripheral position of the break-out point.

Image of the bundle containing the EHT return.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-2) Separate and identify the EHT return:

Tasks:
1) Carefully unsolder all leads from the lug identified in Step 1 (above).
2) 'Untwist' and otherwise separate said leads.
3) Using a resistance indicator, check each lead for continuity to the EHT output contact (i.e. 'output tower') --- the return lead will show a resistance of between 400Ω and 1000Ω -- All other leads should show infinite resistance.

In this case three leads were tied to the lug -- the resistance examination identified the 38 AWG lead as the EHT return (said lead indicated by the pen in the attached image).

Image of separated EHT return --- Note that the associated lug was broken out of the way.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-3) Removal of the form sleeve:

Please note: Far and away the most significant challenges attending this procedure owe to the 'gossamer' nature of #38 and #40 AWG conductors... From this point onward it will behoove the reader to remain mindful of the EHT return whenever handling the assembly - while a severed or broken return lead is not necessarily 'fatal to the cause' - such will greatly complicate matters via the requirement of 'teaseling out' the end of a #40 or even #42 (AWG) lead from the lacquered winding!

Tasks:
1) Carefully dress the return lead out of 'harm's way'.
2) Twist, pry and/or break the form sleeve out from the center of the Aux winding.

Image of EHT winding following removal of the form sleeve. Note the EHT return at ~ "2 O'clock"
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-4) Remove the AUX winding:

Precautions:
A) While 'unraveling' the Aux winding, apply counter-thrust only to the shell --
as opposed to the tyre!
B) While debriding residue from the 'central gap' following removal of the Aux Shell - great care must be exercised is damage to the central layer{s} of the EHT winding to be avoided!

Tasks:
1) Cut all leads attached to all remaining lugs.
2) Using a surgical pick or similar instrument, pry a few 'layers' of the Aux winding into the center such that they may be grasped with forceps.
Image of Aux winding prepared for removal.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

3) Grasp the the loosened layers and begin withdrawing ('unraveling') the Aux winding -- Taking great care to avoid application of tension to the return lead as the periphery is approached.

Image of Aux winding in an intermediate stage of removal.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Note: The EHT return will typically be 'laminated' between the penultimate and ultimate layers of the auxiliary winding bunting.

4) Cautiously break (not tear!) the bunting material away from the return lead.

In the image below you may observe the end of the EHT return (as per the pen) and its emergence from the bunting in the gap intervening the shell and the deflected bunting medial to the remaining lug at 4 O'clock

Image of EHT return embedded in peripheral Aux winding bunting.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of EHT winding following complete removal of Aux winding
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv[/B]

Step 2-5) Remove the AUX Shell:

Tasks:
1) Carefully break, crumble and/or fold the auxiliary shell into the 'central gap' via symmetrical application of force to the distal aspects of the former at quadrature to the plane of the return's emergence.

Under no circumstances attempt to pry the shell from the interstices!!! Doing so will almost certainly damage the EHT winding beyond repair!

2) having thus loosened the shell, carefully remove the fragments being ever mindful of the return...

Images of the EHT winding following removal of the auxiliary shell...

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of EHT winding and debris following removal of the form sleeve, Aux winding, and Aux shell:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Note: Should the reader's EHT winding be potted in silicone (as opposed to merely 'jacketed' as in the case of the demonstration transformer) it will be desirable to arrive at this juncture sans penetration of the potting material -- Should a breach occur, prompt repair via application of electronics grade RTV is advisable...

Step 2-6) Preparation of The Dummy Shell:

Note: Owing to the 'brittleness' of 'Purell' grade polypropylene, use of a sharp instrument is recommended!

Tasks:
1) Excise the base of the polypropylene pharmaceutical vial.
2) Section the (resulting) cylinder longitudinal to its axis.
3) Temporarily mount the dummy shell on the ferrite form -- Verify end clearance ≥ 5mm (form pieces in firm apposition). If end clearance < 5 mm, trim the dummy shell to 'compliance' but try to keep end clearance < 1 cm.

Image of prepared dummy shell
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of correctly 'trimmed' dummy shell on leg of LOPT ferrite form:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-7) Prepare Return Lug:
Tasks:
1) Form a #4 solder lug such that the 'tab' is at a right angle to the plane of the fastener surface.
2) Drill a #66 (~0.83mm) hole through the lug immediately above the bend.

Image of properly prepared lug -- Note the small (#66) hole near the fastener angle.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-8) Installation of the dummy shell:

Image of EHT winding at this juncture - note return lead:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Tasks:
1) Furl the dummy shell, then position it in the central gap from the side of the winding opposite the emergence of the return lead and rotated such that the 'cut' faces opposite the output 'tower'.
2) Using a stylus, scribe, etc - mark the dummy shell at the point 5mm (back) from the edge lateral to emergence of the return.
3) Carefully remove the dummy shell.
4) Using a 7/64” {≈3mm} drill bit, bore through the dummy shell at the point marked in task #2.
5) Liberally coat the dummy shell and gap surfaces with electronics grade RTV. -- Avoid application of RTV to the return lead!
6) Reinstall the shell as described in task #1, taking care to position the cut opposite to the output 'tower', and the bolt hole lateral to the emergence of the return lead.
7) Mount the EHT winding/dummy shell assembly on the ferrite form.
8) Adjust the (linear) position of the winding tyre on the shell such that the former is equidistant from the form piece angles while the end of the shell emerging from the 'return lead side' of the winding tyre extends as far as possible from the winding sans contact with the form piece.
9) Remove the form from the assembly taking care not to alter the relative position of the shell/winding.
10) Manually expand the shell as much as possible -- smooth and 'touch-up' the silicone... --- Again keep the return lead free of adhesive!
11) Allow RTV to cure for at least 72 hours at temps of 7.2°C (45°F) through 15.5°C (60°F) -OR- for at least 48 hours at temps >15.5°C (60°F)

Step 2-9) Installation of the Lug and connection of the return:
Tasks:
1) Carefully insert the #4 bolt from inside the shell.
2) Secure the lug to the top of the shell as shown in the images below.
3) Solder-tin the end of the return lead.
4) Insert ~ 2 mm of the return lead into the #66 hole near the base of the lug then secure it with solder.

Note: It is imperative that the return lead is neither trimmed nor glued at this point! - Please loop any slack as shown in the images.

Images of the assembly; Dummy shell & Lug installed, return connected:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

5) Verify that the DC resistance (lug to output tower connector) -- is that measured in step #2-2, task#3

Step 2-10) Prepare the CPVC Form sleeve:
Tasks:
1) Cut a length of 3/4" id (CTS) CPVC tubing equal to the total length of the form-leg on which it will be placed (In the case of this demonstration 8.5 cm) See the two images immediately below...

Image illustrating desired sleeve dimension
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of form and adjacent CPVC section cut as per task #1
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

2) Cut 'shoulder stirrups' into the CPVC Sleeve:
Note: the stirrups must be sufficiently deep as to allow a slight amount of end-clearance when mounted upon the form (such that form piece apposition is assured).

Image of form pieces and 'prepared' CPVC sleeve
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of form and CPVC sleeve in an intermediate state of assembly
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Image of (temporary) fully assembled form and CPVC assembly
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Step 2-11) Permanently install CPVC form sleeve in EHT winding assembly:

Image of components referenced in this step:
(L to R) CPVC sleeve, EHT winding assembly, Form [core] pieces
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Tasks:
1) Assemble EHT winding, CPVC sleeve and form as shown (below).
2) Using PTFE shims, center EHT winding assembly about CPVC sleeve (both sides).
Note: While the adhesive does not bond PTFE it is, nonetheless, essential that the shims be so formed as to preclude (interlocked) captivity in the former!

Images of mounted and centered EHT winding as seen from 'EHT return side':
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

4) Using acrylic-based 'hot-melt' adhesive, tack the CPVC sleeve to the polypropylene shell at several points each side.
5) Remove form pieces.
6) Fill the space intervening the CPVC sleeve and the PP shell with acrylic-based 'hot-melt' adhesive taking care not to disturb the relative positions of said structures!
7) Allow the adhesive at least 60 Minutes to cool/cure.
8) Withdraw the shims.

Image of assembly immediately following withdrawal of shims as seen from EHT return side.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

9) Fill the 'shim gaps' with acrylic-based 'hot-melt' adhesive.

Image of EHT winding assembly following completed installation of CPVC sleeve.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Identification of components/materials referenced in steps #12 through #15 (inclusive):
1) PTFE insulator.
2) EHT Winding assembly.
3) Form pieces.
4) LOPT Frame.
5) Polyolefin (heat shrink) sleeves.
6) Elastic cushions.
7) Frame ligature.
8) Form standoffs.
9) Reluctance gap spacers (see text).

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

###+++###+++


Step 2-12) Prepare form guides

Prior to proceeding, it is imperative that the form pieces are absolutely free of adhesive residue, etc!

Tasks:
1) Trim two pieces of polyolefin tubing such that they extend the full inside length of each 'winding leg' of the assembled frame (as shown below).
2) With the sleeves in place on the form, clamp or otherwise place form pieces in firm apposition with close attention to alignment of same.
3) Heat-process the polyolefin tubing -- Note: expeditious completion of this step will significantly reduce liability to ferrite breakage (secondary to uneven application of heat) and/or permanent shift of magnetic properties (secondary to excessive temperature)...
4) Allow at least 20 Minute 'cool down' period then carefully disassemble the form such that the heat-processed polyolefin tubes remain installed on each 'half-leg' of a single piece.
5) Trim another sleeve then repeat the above procedure such that one leg is bound by a double layer of polyolefin.




Image of assembled form 'sporting' the unprocessed polyolefin sleeves (Post task #1)
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/preshrink-jpg.101742/

###Improve descriptions below to indicate images follow separation of form pieces####

Image of form piece following processing of sleeves (Post task #4)
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/separated1-jpg.101743/

Image of form piece following processing of second sleeve (on arbitrarily chosen) EHT winding 'leg' (Post task #5)
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/separated2-jpg.101744/

Step 2-13) Fashion and place reluctance gap spacers
Note: Reluctance gaps will be incorporated to reduce liability to saturation (in all cases) and to leave the transformer compatible with 'flyback' topology should same be desired --- That said, this series prefers forward transfer paradigms (as explained in the introduction to this tutorial).

Note: The (.95mm) reluctance gap spacers salvaged from the disassembly process are shown in the "component identification image" for completeness of presentation only --- Based upon core material properties and desired output current, optimal operation requires development of reluctance gaps consistent with the inequality: 0.25mm < Gap < .5mm -- To this end 0.4mm (0.015" nominal) PTFE sheet stock will be used.

Tasks:
1) Cut two small disks of PTFE having maximum major axes slightly less than that of the form piece 'ends'...
2) Check actual spacer thickness with a mechanical vernier micrometer (Resolution = 1 um -OR- 1/10,000 inch) note that a 'metric' instrument offers slightly finer resolution (inasmuch as 0.0001"=2.54 um)
3) Very lightly smear one side of each spacer with electronics grade RTV.
4) Place each spacer (RTV side down) flat upon each form piece end (inside each polyolefin sleeve).
5) Via firm tamping with a pencil eraser or similar implement assure that the RTV film 'tacks' the spacers to the form piece ends...

Image showing representative spacer and measurement of thickness:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/airgapmic-jpg.101728/

Image showing correct pre-assembly placement of spacers:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/airgapinplace-jpg.101727/


Step 2-14) Assemble LOPT

Tasks:
1) Tack elastic cushions and form standoffs to frame then position as shown:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptframechoks-jpg.101732/

2) Verify that the reluctance gap spacers are fast to the form piece.
3) Hold the frame ligature in lengthwise apposition with the utmost facet of the form's EHT winding leg. (i.e. the leg carrying a double thickness of polyolefin).
4) Carefully place the EHT winding assembly over the form piece leg and ligature such that the shoulder stirrup engages the form piece as shown below:

Form ligature in pre-assembly position:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/asm1-jpg.101729/

Views of EHT winding, form piece and form ligature in intermediate state of assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/lopt_preasmby-jpg.101731/
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptpartialasmby-jpg.101735/

5) Slowly press the opposite form piece into place allowing time for displacement of air from the polyolefin tubes.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptpreframe-jpg.101737/

6) Install transformer assembly into frame such that the ligature strap ends extend through the 'ears' of the frame.

7) Very carefully but firmly clamp the assembly preparatory to fastening...
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptpresoldered-jpg.101739/

8) Solder ligature ends to frame
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptpostsoldered-jpg.101736/

Step 2-15) Install lateral insulator

Tasks:
1) Form a cardioid of 0.093" (AKA "93/1000'ths") PTFE sheet stock as per item #1 in the image (immediately below):
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/lopt_partsnum-jpg.101730/

2) Size, shape and fit the insulator to the EHT winding assembly in a manner consistent with the following images but do not apply adhesive at this time.
Note that the insulator must be trimmed to closely fit the shell and extend beyond the peripheral aspect of the EHT winding by at least 1 cm.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/final-jpg.101745/
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/strikeshldside-jpg.101748/

3) Having properly formed the insulator, 'de-gloss' one side of same using '00' grit emery cloth/paper.
4) Apply liberal quantities of electronics grade RTV silicone to the appropriate surfaces of the EHT winding assembly and the entirety of the 'sanded' side of the insulator.

5) Attach the insulator to the EHT winding assembly as shown in the above images.
6) Apply an excess of electronics grade RTV to the exposed side of the insulator and adjacent areas of the EHT winding assembly...
7) Distribute the RTV over the insulator and EHT winding assembly surfaces such that an interlocking bond is established.
8) Position the LOPT 'insulator up' then allow at least 48 hours curing time.

=== Part 3 --- Operational testing ===

 

@Aleph(0) Et al

Re: The Tutorial (post #939) completed tasks:

-- Updated all expansion links such that they point to their respective unique glossary entries (in my blog).
-- Added new (and, where appropriate, redundant) links.
-- Renamed glossary entries for clarity/'user friendliness' -- New form = "Expansions and glossary Entry #nn"

Please note that, at this juncture, the glossary entries contain expansions only -- Said entries to be 'filled out' as required...

Best regards
HP

 

Yo Hp! The glossary links are beautiful! You were SO right abt it being worthwhile to make separate blog entries for each glossary term! It's just so much more professional and readable than linking to the top of a list or bugging readers with inline expansions!

So I just received your e abt the mini course on building a meter for floating HV supplies! Looking great! The only thing I'd add is a source for that handy rotary switch! That kind of versatility belongs in everybody's lab stock! I think it's awesome that you're including features for measurement of single-ended voltages too! I agree that separate calibration trimmers for each polarity is a good plan b/c the dropping resistors are only 15% tolerance and that's a few kV of discrepancy if they happen to be poorly matched! Four switch positions are needed anyway so doing it right isn't even extra work! Wow! It's good you're getting it done now b/c @Aleph(0) looks like getting back just in time for you to head out to Dayton! But hey! I know Aleph has done a lot of work on the EHT course (unlike yours truly) so I hope you both know I'm just giving her a hard time abt slacking off! Seriously! I wouldn't have her job for anything! I mean talk about "uneasy rests the head that wears the crown" Jebus!

So I don't have enough time to respond to past posts right now now But skipping Daytona has gotten me all "studied ahead" so I'll have some quality free time starting in June! I really hope I can be of help! Thank you for keeping me a member of the team even though I've contributed absolutely nothing to date It's not a gaming addiction it's just that my free time is totally fragmented

Hp please listen to this tune! It so exquisitely describes my feelings that I wish I wrote it myself! Hp I know it doesn't change anything! I'm totally at peace with that! I just want you to know how I feel! Not b/c it will change anything but I just need you to know! I don't really know why other than just that knowing that you totally understand how I feel gives me peace of mind.

 

The only thing I'd add is a source for that handy rotary switch! That kind of versatility belongs in everybody's lab stock!

Agreed! - Unfortunately I've been unable to determine the manufacturer let alone locate a source! -- Tell ya what! - I'll post an inquiry to the 'resources' forum

I think it's awesome that you're including features for measurement of single-ended voltages too!

Indeed! I felt same would be appreciated by our (long-suffering) readers! -- Pleased you approve!

I agree that separate calibration trimmers for each polarity is a good plan b/c the dropping resistors are only 15% tolerance and that's a few kV of discrepancy if they happen to be poorly matched! Four switch positions are needed anyway so doing it right isn't even extra work!

--Emphasis added--
Exactly!

It's good you're getting it done now b/c @Aleph(0) looks like getting back just in time for you to head out to Dayton!

Later than that in the event of a US Govt shutdown at the end of this month

so I hope you both know I'm just giving her a hard time abt slacking off!

It's not a gaming addiction it's just that my free time is totally fragmented

Apt analogy, that!

So I don't have enough time to respond to past posts right now now

For all that, it seems you've found time to shame the 'electrics vs electronics' crowd

Thank you for keeping me a member of the team even though I've contributed absolutely nothing to date

Was I to start dismissing Tutorial contributors for inaction, fairness would require that I begin with the gal in the mirror!

Hp please listen to this tune! It so exquisitely describes my feelings that I wish I wrote it myself!

Very well... I did listen and I must say it makes me rather sad inasmuch as it speaks of a great deal of 'emotional energy' which could be so much better invested!
Passing fancies are just that! -- Whereas attainment and apprehension of knowledge are nothing less than our species' 'manifest destiny' as it were! - JC, on my word! Your sentiments in this regard will pass! - To paraphrase (of all people) @Aleph(0) -- You've merely lost perspective - please mind that you don't lose opportunity (via study/academic achievement) in the bargain

Very best regards and please take care
HP