I’ve noticed that my simulation plots do not include the part of the line from the starting value to the first step. For example, I created a simple transistor biasing example with a base resistor and a swept voltage source for Vbb to show how a failing battery could throw off the operating point in this type of biasing.
To simulate a failing single cell alkaline, I use a starting voltage of 1, a final voltage of 1.5, and a step of 0,1V. The line on the simulation plot starts at 1.1V and extends to 1.5V. I would have expected it to start at 1.0V and extend to 1.5V.
EDIT: I did not see a way to attach a screenshot, but if you’re interested, I have one at: http://horton.sdf.org/plot-screenshot.jpg
If this is a bug, I will submit it as such. I didn’t see anything listed in my search. But, if it’s a “feature” can someone please explain this behavior to me?
I’m using KiCAD 5.19 for Windows 10. I believe this is the latest stable version. Here’s the net list for my circuit:
.title KiCad schematic
V1 Vcc GND DC 9
V2 Vbb GND DC 1.5
Q1 GND Net-_Q1-Pad2_ Out1 2N3904
Q2 GND Net-_Q2-Pad2_ Out2 2N3904
R1 Net-_Q1-Pad2_ Vbb 9.1k
R2 Vcc Out1 10k
R4 Vcc Out2 10k
R3 Net-_Q2-Pad2_ Vcc 82k
Q3 GND Net-_Q3-Pad2_ Out3 2N3904
R6 Vcc Out3 10k
R5 Net-_Q3-Pad2_ Out3 51k
Q4 Net-_Q4-Pad1_ Net-_Q4-Pad2_ Out4 2N3904
R7 Net-_Q4-Pad2_ Vbb 8.2k
R8 Vcc Out4 10k
R9 Net-_Q4-Pad1_ GND 100
.model 2N3904 NPN(IS=1E-14 VAF=100
+ Bf=300 IKF=0.4 XTB=1.5 BR=4
+ CJC=4E-12 CJE=8E-12 RB=20 RC=0.1 RE=0.1
+ TR=250E-9 TF=350E-12 ITF=1 VTF=2 XTF=3 Vceo=40)
.end
