Why does the vertical bar on the y-axis of the waveform viewer light up sometimes? What is it measuring? I am including a picture below with a white arrow pointing to it for example.
I am including a simple schematic of a BJT emitter follower that is not biased correctly. It’s the only way I can get the little vertical bar on the y-axis to light up. It has to be measuring something. What is its function? I have skimmed over the documentation on the kskelvin gitub and there is no mention of what the function of this is. It’s not implied anywhere in the documentation, or the YouTube tutorial videos.
I replicated your circuit but cannot reproduce the symptoms you observed. Could you upload your .qsch file? Or, are you running the latest version of Qspice?
Well… The 2N3904 is not in the Qspice standard library. Did you import this model from somewhere else, or are you actually running your simulation with a warning like “defaults assumed”? I tried with warning “defaults assumed” but still did not observe this spike at 0s.
BJT-InQuestion.qsch (5.8 KB)
Nano81_Schematic.qsch (5.8 KB)
Et tu, Brutus… Et tu??
That initial spike is from the model parameter XCJC, in Qspice standard library, all NPN devices without this parameter and therefore, no such issue in using Qspice standard model. With your 2N3904 model and remove XCJC, this spike will be removed.
Nano81_Schematic (XCJC).qsch (6.4 KB)
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Yes. That worked for me also. Thank you. I haven’t been using any Qspice standard model transistors. I should probably try to do that.
The problem was reported to Mike, and a fix has been delivered in the latest Qspice update.
Revision History : 02/10/2025 Fixed a problem handling BJT model parameter XCJC.
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