We will now analyze the circuit for beta sensitivity by running a Sweep analysis.
1. Double click on the DR. SPICE™ icon to begin.
2. Select ckt2.cir from the C:\DRSPICE\EXAMPLES directory, then check the Interactive button.
3. Click OK
Within the editor window you will see this circuit:
CKT2.CIR Netlist
4. From the Analysis menu select Sweep Analysis.
Sweep/Step Command Editor
5. Click on the Model Parameter radio button.
6. Select Type: BJT
7. Select Name 2n2222
8. Select Parameter bf
A current value is listed at 294.15.
9. Under Sweep Type, select the List radio button and enter the following values:
250 300 350
NOTE: It is not necessary to punctuate entries.
10. Click OK.
You are now asked to select which waveform you wish to view
11. For this example, select the v(out) waveform.
12. Click OK.
13. When the simulation is completed, Select TRAN from the Simulation Menu.
Simulation Menu
A “Plot Vector” dialog box appears; within dialog box
14. Click on the Clear button.
15. Click on the “All in Group” box.
16. Click on the v(out) waveform.
17. Click OK.
Plot Vector Dialog Box
Notice that three waveforms are plotted almost on top of each other.
Three Waveforms Unmagnified
18. You can zoom in on the three waveforms until the distinct waveforms are visible, by using your left mouse button. Click and drag within the plot window to zoom in on the individual waveforms.
Three Waveforms Magnified