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Amplifer Design

Started by Cursitor Doom October 13, 2019
Greetings, gentlemen,

This is the schematic of the CRO x-amplifier I've been investigating 
lately. It's supposed to provide sufficient potential difference to the x 
plates in the tube so as to sweep the electron beam left to right in 
accordance with the timebase setting:

https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/

At first I thought this was operating as some kind of complimentary pair 
chain of stages, but it's only quasi-complimentary and I can't fully 
understand how it works. The signal path is shown in slightly heavier 
lines. It starts off conventionally enough, with a sawtooth sweep 
waveform of approx half a volt applied to the base of Q10, but then why 
does it then passed to the *emitter* of Q15? This is the part I'm 
struggling to understand most. 

What is the name for this type of configuration and why is the input 
signal to Q15 being applied to its emitter rather than its base?
Thanks.


(if it were *truly* complimentary/push-pull then I'd have thought there 
should be a *minus* 158V supply for the final stage of the lower chain, 
but it states +158V which makes no sense to me).



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On 13/10/2019 19:40, Cursitor Doom wrote:
> Greetings, gentlemen, > > This is the schematic of the CRO x-amplifier I've been investigating > lately. It's supposed to provide sufficient potential difference to the x > plates in the tube so as to sweep the electron beam left to right in > accordance with the timebase setting: > > https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/ > > At first I thought this was operating as some kind of complimentary pair > chain of stages, but it's only quasi-complimentary and I can't fully > understand how it works. The signal path is shown in slightly heavier > lines. It starts off conventionally enough, with a sawtooth sweep > waveform of approx half a volt applied to the base of Q10, but then why > does it then passed to the *emitter* of Q15? This is the part I'm > struggling to understand most. > > What is the name for this type of configuration and why is the input > signal to Q15 being applied to its emitter rather than its base? > Thanks. > > > (if it were *truly* complimentary/push-pull then I'd have thought there > should be a *minus* 158V supply for the final stage of the lower chain, > but it states +158V which makes no sense to me). > > >
Q10 and Q15 are a diff-amp or long-tailed pair. Q11 is the tail current source. piglet
On 13/10/19 19:40, Cursitor Doom wrote:
> Greetings, gentlemen, > > This is the schematic of the CRO x-amplifier I've been investigating > lately. It's supposed to provide sufficient potential difference to the x > plates in the tube so as to sweep the electron beam left to right in > accordance with the timebase setting: > > https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/
Why do you post that on a Russian company's servers, rather than dropbox? Aren't you allowed to use/access dropbox or another western company's servers?
Tom Gardner wrote...
> > On 13/10/19 19:40, Cursitor Doom wrote: >> Greetings, gentlemen, >> >> This is the schematic of the CRO x-amplifier I've been investigating >> lately. It's supposed to provide sufficient potential difference to the x >> plates in the tube so as to sweep the electron beam left to right in >> accordance with the timebase setting: >> >> https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/ > > Why do you post that on a Russian company's servers, > rather than dropbox? > > Aren't you allowed to use/access dropbox or another > western company's servers?
Also, is your name Paul B. ? -- Thanks, - Win
On Sun, 13 Oct 2019 12:35:25 -0700, Winfield Hill wrote:

> Tom Gardner wrote... >> >> On 13/10/19 19:40, Cursitor Doom wrote: >>> Greetings, gentlemen, >>> >>> This is the schematic of the CRO x-amplifier I've been investigating >>> lately. It's supposed to provide sufficient potential difference to >>> the x plates in the tube so as to sweep the electron beam left to >>> right in accordance with the timebase setting: >>> >>> https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/ >> >> Why do you post that on a Russian company's servers, >> rather than dropbox? >> >> Aren't you allowed to use/access dropbox or another western company's >> servers? > > Also, is your name Paul B. ?
Yup, as in Burridge. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
On Sun, 13 Oct 2019 20:08:02 +0100, Piglet wrote:

> Q10 and Q15 are a diff-amp or long-tailed pair. Q11 is the tail current > source.
Well I did suspect that initially, Erich, but the input signal is shown only applied to the base of *one* of those transistors! -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
On Sun, 13 Oct 2019 18:40:01 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

>Greetings, gentlemen, > >This is the schematic of the CRO x-amplifier I've been investigating >lately. It's supposed to provide sufficient potential difference to the x >plates in the tube so as to sweep the electron beam left to right in >accordance with the timebase setting: > >https://yandex.com/collections/card/5da36a58f05bf23ffde0742e/ >
I couldn't see that at useful resolution. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Cursitor Doom wrote...
> >On Sun, 13 Oct 2019 12:35:25 -0700, Winfield Hill wrote: > >> Also, is your name Paul B. ? > > Yup, as in Burridge.
Hi Paul, nice to meet you! -- Thanks, - Win
On Sun, 13 Oct 2019 13:21:14 -0700, Winfield Hill wrote:

> Hi Paul, nice to meet you!
Gleichfalls, Win. :) -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
On Sun, 13 Oct 2019 13:17:04 -0700, jlarkin wrote:

> I couldn't see that at useful resolution.
I know; it's a PITA but there's nothing I can do as I pulled it off a website myself. I've posted 2 versions, so you might see it better with the enhanced one where I've tweaked things up a bit. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.