Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Glossary
Glossary
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th September 2019, 09:37 AM   #11
Ketje is online now Ketje  Belgium
diyAudio Member
 
Ketje's Avatar
 
Join Date: Dec 2012
Location: Flanders
Without the schematic it is still not very clear.
I would write it like A = µRa / [ Ri + Ra + ( µ+1 ) Rk ]
Since it's about gain, it's obvious that µ and Ri are dynamic values as in µ=S.Ri
Mona
Attached Images
File Type: png form.png (10.6 KB, 70 views)
  Reply With Quote
Old 16th September 2019, 10:53 AM   #12
Rod Coleman is offline Rod Coleman  United Kingdom
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
Glossary
Greetings! Symbols were a great deal less standardised than today, especially across geographic variations. Ketje is using the Philips symbols, which appear in a large amount of literature from Europe (snapshot attached from the Philips technical manual).

Still, even within Philips, this is not held consistently. Mullard was a Philips company, but their 1948 data book defines anode resistance symbols as

ra (inside valve)
Ra (outside valve)

Marconi Osram (1951 data) uses this same standard. But before we can say that British manufacturers were consistent, we find that Brimar used R for loads and Ra for internal anode resistance.

You really have to know in advance what the writer meant by any symbol in historical literature, or at least carefully figure it out.

For drawing new schematics or design-definitions, the small-signal & large signal conventions that Rayma links to are widely used in modern electronics, and are far preferable, IMHO. So Ra, Za, Rp, Zp for external loads (small signal values), and ra (or rp) for internal small-signal resistance are examples of my preferences.
Attached Images
File Type: png Resistance-symbols.png (12.5 KB, 65 views)
  Reply With Quote
Old 16th September 2019, 03:23 PM   #13
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Hearinspace View Post
Thanks for that. It makes it clear and easy to remember ,
. . . . . though it still bugs me a little that we can't use the notation to learn the principle, we have to already know the principle in order to interpret the notation. I don't like the idea much.
Stick with more recent books and it should be more consistent.
  Reply With Quote
Old 16th September 2019, 04:56 PM   #14
Ketje is online now Ketje  Belgium
diyAudio Member
 
Ketje's Avatar
 
Join Date: Dec 2012
Location: Flanders
Using lower case for AC and upper case for DC parameters is not as simple as that.
In the formula A = µRa / [ Ri + Ra + ( µ+1 ) Rk ], Ra and Rk doesn't have to be only for DC.
Ra can not only be the actual resistance to + but parallel to it the (capacitor coupled) grid resistor of the next stage, or a transformer or even a CCS.
Same thing for Rk, a LED or a CCS...
Then there also is the possebility of a filter as a load.
More exact would be A = µZa / [ Zi + Za + (µ+1) Zk ], yes also Zi because of anode capacity.
Conclusion, better explane the variables before using them.
Mona
  Reply With Quote
Old 16th September 2019, 05:01 PM   #15
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Yes. Useful symbol conventions aid understanding, but they are not physical laws.
  Reply With Quote
Old 16th September 2019, 06:10 PM   #16
kodabmx is offline kodabmx  Canada
Spreading triode love.
diyAudio Member
 
Join Date: Oct 2011
Location: Toronto
Glossary
Quote:
Originally Posted by Hearinspace View Post
Thanks for that. It makes it clear and easy to remember ,
. . . . . though it still bugs me a little that we can't use the notation to learn the principle, we have to already know the principle in order to interpret the notation. I don't like the idea much.
I feel the same about current... In my mind (and in reality), current flows from negative to positive. "Conventional" current should be called "anti-current" IMHO.
Attached Images
File Type: png Current_notation.svg.png (58.4 KB, 43 views)

Last edited by kodabmx; 16th September 2019 at 06:13 PM.
  Reply With Quote
Old 17th September 2019, 03:12 AM   #17
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
Quote:
Originally Posted by Hearinspace View Post
...it still bugs me a little that we can't use the notation to learn the principle, we have to already know the principle in order to interpret the notation....
Because history. Techs had to fumble with the "principle" before they could do "notation" (to know what to notate).

And as said, there was not universal agreement on notation. Read electronics magazines of old. From the 1930s through the 1960s there were many "recommendations" in the US, and different ones in Europe etc. (The change from mmf thru uuf to pF happened much earlier in much of Europe than in the US.) The IEEE has been working for harmony, but each clique clings to habit, and nobody of universal respect is harmonizing small-tube notation today.
  Reply With Quote

Reply


GlossaryHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
GLOSSARY... Where do you find it? stereodude27 Everything Else 1 19th October 2011 11:02 AM
Glossary for abbreviations - Help! crispycircuit Everything Else 1 3rd February 2010 10:06 PM
Gainclone Glossary Ropie Chip Amps 0 28th April 2004 09:13 PM
POWER AMP Glossary chris ma Everything Else 0 22nd October 2003 04:24 PM


New To Site? Need Help?

All times are GMT. The time now is 06:59 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki