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Does a capacitor charges smooth, or in stairs?

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Labrat101:

--- Quote from: T3sl4co1l on June 08, 2020, 10:23:04 pm ---A mechanical schematic, showing the physical components and connections yes, but that's not what I asked!

Tim

--- End quote ---
I suggest you take this question to RoGeorge
Who's idea it was. We have just just tried to figure out if his hair brain theory is correct.
There are No 2 components that will be
Anatomically the same. . (Close enough.)
You would have to use the exact same components for all experiments.
Watch his videos.  And you can decide
How he makes a square peg fit in a round hole .
My experiments proved nothing other than I can pulse a capacitor to failure point.
RNS.
I know what you want .. but these things were not give in any of his documentation.
So that's why his theory is not possible to solve . .
Even two lengths of coax from 2 different rolls Will not be exactly the same.
..
We would all be the same ..
Enjoy.

StillTrying:

--- Quote from: Labrat101 on June 08, 2020, 12:28:33 pm ---Is this the staircase or is it something else
--- End quote ---

I think it's probably something else, maybe oscillations (which happen all the time) superimposed on the the discharge curve.

The middle of the video is definitely describing transmission line effects, along the plates of the capacitor, so I chose a capacitor that was 2.5m long. :)

To get a good view of effects only a few ns wide you have to get rid of all those long wires. To get the GND and resistor as close as possible to the GND and gates of the 74AC14 I soldered them to the back of the board, and arranged the end of the cable so I didn't have to use any GND clip on the scope probe.

rhb:
Thanks for the photo.  I shall repeat the experiment with either a 1 GHz 7104 and 36 ps step or an 11801 with a <20 ps step and 20 GHz sampling head and varying lengths of coax.  Likely the 11801 as I have some other experiments I need to set it up for.

Both of those should give nice neat staircases as they have very little overshoot.

Have Fun!
Reg

rhb:
OK  These are with a Tek 11801 & 20 GHz SD-24 sampling head.  I fed the coax stub through a 150 ohm resistor.

10-12 ft coax



50 cm



16 cm



(sorry about the burred image.  I didn't notice it until I posted it)



The 250 mV step has a <20 ps rise time.  The only thing changing is the travel time and the capacitance.  As the coax has approximately the same capacitance per foot, the number of steps stays constant and the only thing that changes is the time delay for each step.  If I expand the vertical scale a lot I can count about 13 steps before the steps fall below the noise and quantization.

Q.E.D.
Quod erat demonstrandum. 
It has been shown.

Have Fun!
Reg

rhb:
Just for fun, here's a close up of the trailing part of the stairstep for a 30 cm piece of high quality RG402 with >1024 sweeps averaged and at maximum gain.  The little bump at the top of the step is connector saver and wear on the 3.5 mm connector of the SD-24.



Reg

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