0
\$\begingroup\$

I have done a “parametric sweep” of the DC voltage source VCC ranging from 0 to 30 V and on the current source with values of iB = 0,50,100,150,200, and 250 µA.

NPN BJT

Below is the plot iC vs vCE (vCE being the X axis). The X axis shows only values from 0 to 10 V.

iv plot

Why is there only 5 lines on the plot if I have swept iB for 6 values?

\$\endgroup\$
  • \$\begingroup\$ As a sanity check you could plot Ib and ensure you are getting 6 sweeps \$\endgroup\$ – sstobbe Oct 27 '19 at 23:35
  • \$\begingroup\$ why do you show only 4 step currents in 1 unlabelled plot? for an unidentified setup? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Oct 27 '19 at 23:53
  • \$\begingroup\$ You say you plotted 6, you ask why you only see 5, I see 4. What's R_C and Beta? \$\endgroup\$ – StainlessSteelRat Oct 27 '19 at 23:57
  • \$\begingroup\$ @StainlessSteelRat I believe the 5th (and maybe 6th, I need to do the math) is displayed as cutoff. \$\endgroup\$ – KingDuken Oct 28 '19 at 2:49
0
\$\begingroup\$

I plotted Ib as a sanity check and got 5 values, so I added 300uA to the sweep. This gave me six sweeps with 250uA included.

This is the the iv plot with Ib. iv plot w/ Ib

This is the the iv plot with Ic. iv plot with Ic

The fact that there is one fewer curve than expected is just an issue with OrCAD. I did a DC Sweep w/ secondary sweep (the primary was for Vcc) with initial point I=0.1uA (since we cannot start from exactly 0), ending point of 300uA and increments of 50uA.

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.