Analog Electronics with LabVIEW®

B.6. SPICE Solution for I_C versus V_CE of the Measurement Circuit

All components of base current are those from (B.12) (forward mode) and (B.14) (reverse mode). These are summed together to obtain the following expression for the general bias case:

Equation B.27

In the measurement circuit of the project on the output characteristic of the BJT, the circuit will provide a current source at the input and I_B (to a good approximation) will be a constant. However, in the event that a precision solution for I_B and V_BE is required, it can be obtained by equating (B.27) to I_B from the input circuit equation (Fig. B.12), which is

Equation B.28