Reply by Cydrome Leader October 12, 20202020-10-12
Cydrome Leader <presence@mungepanix.com> wrote:
> Jim Jackson <jj@franjam.org.uk> wrote: >> On 2020-09-11, Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> wrote: >>> On 11.09.20 21:34, Jim Jackson wrote: >>>> On 2020-09-10, Phil Allison <pallison49@gmail.com> wrote: >>>>> On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote: >>>>>> yuenhonkeung@gmail.com wrote: >>>>>>> Many books told me that current leads voltage by 90 degrees in capacitor. >>>>>>> So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >>>>>>> >>>>>>> Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >>>>>> >>>>>> Good video. I like the mention of the ground lead connection. >>>>> >>>>> ** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. >>>>> >>>>> In phase = diagonal line >>>>> >>>>> 45 degree shift ( -3db_) = ellipse. >>>>> >>>>> 90 degree = circle. >>>>> >>>> >>>> Ah! the memories - back in school in the 1960's, baffling the physics >>>> teacher by hooking up the sig. gens to not only the front X input but >>>> the Y input at the back - and another on the Z input to get travelling >>>> spots. >>>> >>> Aaah! Those old times.... >>> I used x,y input, to put text on a scope screen, >>> with 2 dao's from an ordinary 80-286 computer. >>> Worked fine. >> >> Lovely - but in the late 1960's the school I was at didn't have a >> computer :-) >> >> But back in the 40's scopes, well CRTs, were used as RAM for some of the >> first progammable computers. >> >> https://en.wikipedia.org/wiki/Williams_tube >> >>> just visit each point which needed licht, >>> movement from one point to the next, was fast enough >>> to only show as dark lines, > > When did they stop making those memory CRT tubes for scopes and raster > display for old computers?
correction, vector displays.
Reply by Cydrome Leader October 12, 20202020-10-12
Jim Jackson <jj@franjam.org.uk> wrote:
> On 2020-09-11, Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> wrote: >> On 11.09.20 21:34, Jim Jackson wrote: >>> On 2020-09-10, Phil Allison <pallison49@gmail.com> wrote: >>>> On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote: >>>>> yuenhonkeung@gmail.com wrote: >>>>>> Many books told me that current leads voltage by 90 degrees in capacitor. >>>>>> So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >>>>>> >>>>>> Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >>>>> >>>>> Good video. I like the mention of the ground lead connection. >>>> >>>> ** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. >>>> >>>> In phase = diagonal line >>>> >>>> 45 degree shift ( -3db_) = ellipse. >>>> >>>> 90 degree = circle. >>>> >>> >>> Ah! the memories - back in school in the 1960's, baffling the physics >>> teacher by hooking up the sig. gens to not only the front X input but >>> the Y input at the back - and another on the Z input to get travelling >>> spots. >>> >> Aaah! Those old times.... >> I used x,y input, to put text on a scope screen, >> with 2 dao's from an ordinary 80-286 computer. >> Worked fine. > > Lovely - but in the late 1960's the school I was at didn't have a > computer :-) > > But back in the 40's scopes, well CRTs, were used as RAM for some of the > first progammable computers. > > https://en.wikipedia.org/wiki/Williams_tube > >> just visit each point which needed licht, >> movement from one point to the next, was fast enough >> to only show as dark lines,
When did they stop making those memory CRT tubes for scopes and raster display for old computers?
Reply by Jim Jackson September 13, 20202020-09-13
On 2020-09-11, Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> wrote:
> On 11.09.20 21:34, Jim Jackson wrote: >> On 2020-09-10, Phil Allison <pallison49@gmail.com> wrote: >>> On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote: >>>> yuenhonkeung@gmail.com wrote: >>>>> Many books told me that current leads voltage by 90 degrees in capacitor. >>>>> So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >>>>> >>>>> Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >>>> >>>> Good video. I like the mention of the ground lead connection. >>> >>> ** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. >>> >>> In phase = diagonal line >>> >>> 45 degree shift ( -3db_) = ellipse. >>> >>> 90 degree = circle. >>> >> >> Ah! the memories - back in school in the 1960's, baffling the physics >> teacher by hooking up the sig. gens to not only the front X input but >> the Y input at the back - and another on the Z input to get travelling >> spots. >> > Aaah! Those old times.... > I used x,y input, to put text on a scope screen, > with 2 dao's from an ordinary 80-286 computer. > Worked fine.
Lovely - but in the late 1960's the school I was at didn't have a computer :-) But back in the 40's scopes, well CRTs, were used as RAM for some of the first progammable computers. https://en.wikipedia.org/wiki/Williams_tube
> just visit each point which needed licht, > movement from one point to the next, was fast enough > to only show as dark lines,
Reply by Sjouke Burry September 11, 20202020-09-11
On 11.09.20 21:34, Jim Jackson wrote:
> On 2020-09-10, Phil Allison <pallison49@gmail.com> wrote: >> On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote: >>> yuenhonkeung@gmail.com wrote: >>>> Many books told me that current leads voltage by 90 degrees in capacitor. >>>> So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >>>> >>>> Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >>> >>> Good video. I like the mention of the ground lead connection. >> >> ** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. >> >> In phase = diagonal line >> >> 45 degree shift ( -3db_) = ellipse. >> >> 90 degree = circle. >> > > Ah! the memories - back in school in the 1960's, baffling the physics > teacher by hooking up the sig. gens to not only the front X input but > the Y input at the back - and another on the Z input to get travelling > spots. >
Aaah! Those old times.... I used x,y input, to put text on a scope screen, with 2 dao's from an ordinary 80-286 computer. Worked fine. just visit each point which needed licht, movement from one point to the next, was fast enough to only show as dark lines,
Reply by Jim Jackson September 11, 20202020-09-11
On 2020-09-10, Phil Allison <pallison49@gmail.com> wrote:
> On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote: >> yuenhonkeung@gmail.com wrote: >> > Many books told me that current leads voltage by 90 degrees in capacitor. >> > So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >> > >> > Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >> >> Good video. I like the mention of the ground lead connection. > > ** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. > > In phase = diagonal line > > 45 degree shift ( -3db_) = ellipse. > > 90 degree = circle. >
Ah! the memories - back in school in the 1960's, baffling the physics teacher by hooking up the sig. gens to not only the front X input but the Y input at the back - and another on the Z input to get travelling spots.
Reply by Phil Allison September 10, 20202020-09-10
On Monday, August 17, 2020 at 3:59:41 PM UTC+10, Cydrome Leader wrote:
> yuenhonkeung@gmail.com wrote: > > Many books told me that current leads voltage by 90 degrees in capacitor. > > So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. > > > > Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A > > Good video. I like the mention of the ground lead connection.
** If the presenter had simply used an analogue scope - he could have employed a Lissajous pattern to prove the fact is a few seconds. In phase = diagonal line 45 degree shift ( -3db_) = ellipse. 90 degree = circle. ..... Phil
Reply by Cydrome Leader September 9, 20202020-09-09
????????? Edward Yuen <yuenhonkeung@gmail.com> wrote:
> On Monday, 17 August 2020 at 13:59:41 UTC+8, Cydrome Leader wrote: >> yuenho...@gmail.com wrote: >> > Many books told me that current leads voltage by 90 degrees in capacitor. >> > So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. >> > >> > Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A >> Good video. I like the mention of the ground lead connection. > Thanks!
I get a good laugh out of half melted ground leads on oscilloscopes.
Reply by 袁漢強 Edward Yuen September 3, 20202020-09-03
On Monday, 17 August 2020 at 13:59:41 UTC+8, Cydrome Leader wrote:
> yuenho...@gmail.com wrote: > > Many books told me that current leads voltage by 90 degrees in capacitor. > > So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. > > > > Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A > Good video. I like the mention of the ground lead connection.
Thanks!
Reply by Cydrome Leader August 17, 20202020-08-17
yuenhonkeung@gmail.com wrote:
> Many books told me that current leads voltage by 90 degrees in capacitor. > So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory. > > Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A
Good video. I like the mention of the ground lead connection.
Reply by August 10, 20202020-08-10
Many books told me that current leads voltage by 90 degrees in capacitor. 
So, I designed an experiment to show that it is true. You can do the experiment at home or in the laboratory.

Here is my experiment in youtube: https://www.youtube.com/watch?v=wjQsyLv0X7A