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Experiment to show that current leads voltage by 90 degrees in capacitor (Using RC circuit and Oscilloscope)

Started by Unknown August 10, 2020
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
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.
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!
????????? 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.
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
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.
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,
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,
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?
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.