Procedure

• SimIC_VCE.vi simulates the output characteristic measurement and associated curve fitting. Data are supplied from an actual measurement from any sample IC_VCEsub.vi. The data include I_C versus V_CE and V_BE versus V_CE.
  
  
• Copy and paste the two data sets from the sample (saved Front Panel or log data) IC_VCEsub.vi. Set up all values in the Digital Controls. The information will be used to compute and display the output characteristic, measured and SPICE, and various parameters and dc variables in the Digital Indicators. Parameters βDC and IS are computed for VCE = VBE, according to the definitions. VAF is computed from a selected range of β_DC from the active region. (Continued below.)

  

  
  
  
• Run the VI and re-run while adjusting BR for the best fit. Use a small VCEmax for this. Verify that VCEmin < VCEmax for this simulation. Note that for the best fit, the SPICE curve goes from slightly greater to slightly less than the measured data with increasing VCE in the saturation region. Re-run for computing VAF in various ranges (e.g., 1 V to 3 V, 2 V to 4 V, etc). Note that VAF varies, and depends on the voltage range, unlike the ideal SPICE basic model. Of primary interest is the evaluation range of 1 V to 3 V, as this brackets the bias voltage of 2 V of the amplifier project, Project C1. Default this case.
  
  
• Note also that the curves will fit in the active region for any combination of VBB and RB. However, the βDC value will only be correct for the actual circuit values. For clarity on this point and others, the computations will be repeated in the Mathcad project file. Save the results.