Components

Same circuit as in PB.4

LabVIEW Computations

SPICE I_C versus V_CE. This is performed with subVI SPICE.vi.

Straight-line curve fit from active-region data:

I_Co ≡ I_C(V_CE = 0) (active-region extrapolation)

VAF = Slope/I_Co

Procedure

• Open subVI, IC_VCEsub.vi. This VI will send out a value of VBB and sweeps VCC to sweep VCE. The maximum VCE is set for 4 V. Set the value of the resistors. Run and re-run while setting VBB for an active-region collector current of about 0.5 mA. Note that at this collector current, a maximum VCE of 4 V should be attainable as the circuit was designed (PB.3, PB.4) for I_Cmax ≈ 1 mA for V_Rc ≈ 9V. Default and save.
  
  

  

• Now open VI, IC_VCE.vi. Set the value of the resistors. Set VBB from the subVI, IC_VCEsub.vi. Set VCEmax at 1 V. Run the VI and adjust BR for a best fit. Then re-run the VI with VCEmax set at 4 V to obtain a good value for VAF. VAF is computed from data points in the range 1 < VCE <VCEmax. Default and save the Front Panel. Double check to be sure that the subVI is defaulted and saved. The data are used in the output characteristic measurement simulation.