Here is my circuit and waveform.
My scope and testing circuit are complete isolated from the main power source.
I'm trying to achieve to measure the voltage drop through a shunt res to calc the inrush current.
It is hard to measure with average dmm but I got an idea somehow to determine the voltage drop with
my scope and the make the math.
If that is actually possible to do with a scope.
btw. when I try to simulate this circuit and measure it with LTS and MultiSim I got no reading on the scope and dmm also in the app.
Only 0v.
And here is what LTS simulate when I put the resistor to the positive side.
The blue line is the I(R3)...
I can do whatever I wish with my real circuit I can't get that value like LTS.
Thanks for any help.
If the circuit is actually what is shown in the top picture, the display on the siglent is pretty much what you would expect, except that the time/div seems wrong, but maybe that's just me------I find it hard to decipher the messages on screen shots of DSO screens.
With R= 1.8

& C= 2000uF, your time constant t= CR is 3.96 ms
The common "rule of thumb" says that C may be regarded as fully charged after a time interval of 5CR, or, in this case, 19.8ms.
At switch on, C looks like a short circuit, so the applied voltage appears across R.
(at the same time, maximum current flows through the circuit)
As C charges up, the charge upon it increases, opposing the applied voltage, reducing the current through R, & hence, the voltage across it.
After t=CR, (in this case, 3.96ms) the current through, & hence the voltage drop across, R has fallen to approx 37%'of its initial value.
After 5CR (19.8ms), the current through, & voltage across, R has fallen to that close to zero that it can be neglected.
The charge on C is now "near as dammit" equal to the applied voltage.
Howver, as the TV advertiser says, "But wait!---There's more!"
Your value for R is very small indeed, so your supply needs to reliably source 6.666 amps.
If its reqularion is good enough, or its internal resistance low enough, there is no problem, but if not,
these may modify the amplitude, time durations, or both, distorting the display.
For your simulation, the "pretend 'scope" must be able to show a time duration of 20ms or more to give you a useable display.