UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Reply
 
Thread Tools
Old 15th Nov 2017, 1:43 pm   #21
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,084
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by Argus25 View Post

I could have mentioned, that the basic function e^x is the only function where it equals the value of its own derivative, so if y = e^x then dy/dx = e^x, so the function value at any point equals the rate of change at that point too.
That's beautiful and incredible. I'll take a look at this function in more detail!
Thank you!
__________________
Al
astral highway is offline   Reply With Quote
Old 15th Nov 2017, 1:58 pm   #22
fetteler
Heptode
 
fetteler's Avatar
 
Join Date: Jul 2011
Location: Staffordshire Moorlands, UK.
Posts: 599
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

I reckon you'd enjoy studying a bit of maths Al, certainly looks like it to me

Cheers,
Steve.
__________________
Those who lack imagination cannot imagine what is lacking...
fetteler is offline   Reply With Quote
Old 15th Nov 2017, 4:20 pm   #23
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 4,115
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by astral highway View Post
...in the instance described in the opening paragraph, Q is far less significant determinant than the relationship between inductance and capacitance. Simply, the smaller the capacitance for a given inductance, the greater by far the peak voltage.
Absolutely! If the Q is infinite, the exponential term is just 1, and the equation simplifies to just Volts = Amps x Ohms.

The Ohms is just the reactance of the inductor (or capacitor) at resonance. You can easily prove this by working out the resonant frequency (F = 1 / (2 x pi x √(LC)) ), and putting the frequency into the formula for reactance (X = 2 x pi x f x L). Or do a bit of easy algebra, and you find things just drop out and you get X = √(L/C).

If Q is less than infinity, it's all multiplied by a very slowly decaying function. But unless Q is very low indeed, it hardly decays more than a couple of a percent in the first quarter cycle. So, Q has very little significance on the peak voltage, but inductance and capacitance matter a lot!
kalee20 is offline   Reply With Quote
Old 15th Nov 2017, 7:55 pm   #24
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,084
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by fetteler View Post
I reckon you'd enjoy studying a bit of maths ...

Yes, Steve ! I realise that my enthusiastic 'discoveries' may be a source of benign amusement to those with first or advanced degrees in physics, maths or
engineering -STEM subjects!? I can imagine how it might come across... and there sure is a lot of mathematical expertise on this forum, I'm aware of it.

As I try to establish the stress tolerance of components in a project with lots of RF and voltage knocking about, I may seem to be discovering things in an intuitive way or even from first principles, as I push my mathematical understanding bit by bit. If so, it's true. I don't mind revealing the limits of my knowledge. I do like to be able to model exactly what is happening, even down to the level of a node, even if it takes some effort and discipline.

I don't think I'll be undertaking any more formal study for a while - I already have a masters degree (although clearly not in a STEM subject!) and have other priorities at the moment, but I'm enjoying my informal learning journey immensely.

One of my favourite books of all time, and which has followed me around since my early twenties, is the 'Penguin Dictionary of Curious and Interesting Numbers', by David Wells. I love it! It lists many amazing properties of numbers, rational and otherwise, as well as amazing series. You might really enjoy it if it's still in print?
__________________
Al

Last edited by astral highway; 15th Nov 2017 at 8:06 pm.
astral highway is offline   Reply With Quote
Old 15th Nov 2017, 8:20 pm   #25
Ed_Dinning
Dekatron
 
Join Date: Jan 2004
Location: Newcastle on Tyne, Tyne & Wear, UK.
Posts: 4,547
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Hi Al, if you get a chance have a look at Electronic Engineering magazine. It dates from about 1939 to the late 80's, but the first 30 years are the best with lots of well explained theory linked to practical details. There should be volumes available in the British Library.
Lots of stuff on components, transformers and tuned circuits and some great nomograms so you can graphically find results.

Ed
Ed_Dinning is online now   Reply With Quote
Old 15th Nov 2017, 8:27 pm   #26
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,084
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by Ed_Dinning View Post
... have a look at Electronic Engineering magazine. It dates from about 1939 to the late 80's, but the first 30 years are the best with lots of well explained theory linked to practical details.
That's a great idea, thanks Ed. Any excuse to get to the British Library!

It sounds as if it's a shame that it went out of publication? I'll dig out some of those earlier years and have a look.
__________________
Al
astral highway is offline   Reply With Quote
Old 16th Nov 2017, 1:41 am   #27
fetteler
Heptode
 
fetteler's Avatar
 
Join Date: Jul 2011
Location: Staffordshire Moorlands, UK.
Posts: 599
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by astral highway View Post
Quote:
Originally Posted by fetteler View Post
I reckon you'd enjoy studying a bit of maths ...
Yes, Steve ! I realise that my enthusiastic 'discoveries' may be a source of benign amusement to those with first or advanced degrees in physics, maths or
engineering -STEM subjects!? I can imagine how it might come across... and there sure is a lot of mathematical expertise on this forum, I'm aware of it.
Hi Al,
No amusement here simply admiration and encouragement for someone who is 'out there' with their curiosity. For my part I am well out of my comfort zone these days with my interests
All the best to you,
Steve.

PS When will we see some decent sparks from your work?... Cant wait for the photos!
__________________
Those who lack imagination cannot imagine what is lacking...
fetteler is offline   Reply With Quote
Old 16th Nov 2017, 1:06 pm   #28
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,084
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Quote:
Originally Posted by fetteler View Post
...admiration and encouragement for someone who is 'out there' with their curiosity.
That's nice of you to say, Steve. I appreciate it, thank you.

Quote:
PS When will we see some decent sparks from your work?... Cant wait for the photos!
Well, we had 'first light' yesterday. If you look at the thread, there's a photo of a small but significant corona/plasma at the top of the main inductor.

This was running with a solid state modulator I built for the purposes of modelling behaviour in the main inductors and tuning. I got around 1cm with just 25 volts.

This is less than a 2,000th of the design voltage which will eventually be the domain of the big old power oscillator valve; at 20W RF it is also just 1/750th of the design power!!!

I won't have the bespoke new transformer for a while, so in the meanwhile I'll be focussing on having the right test equipment (building an EHT probe) and making a temporary EHT supply for testing the power oscillator at a small fraction of the eventual full power.

So the spectacle may be a little way off, aiming for New Year!
__________________
Al
astral highway is offline   Reply With Quote
Old 16th Nov 2017, 5:58 pm   #29
astral highway
Nonode
 
astral highway's Avatar
 
Join Date: Nov 2006
Location: London, UK.
Posts: 2,084
Default Re: Transcendental magic: Schade's peak voltage equation and my discovery!!

Typo: 1/200th! (Of design voltage )...
__________________
Al
astral highway is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 1:27 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright ©2002 - 2017, Paul Stenning.