2. The programme about the transistor functioning

To put to the test our model, we insert the transistor in a circuit like in fig.2.

The simulation programme is wrote in Visual Basic and allow, apart from the graphic, to use the objects like the cursors for the parameters' variation.

It's easy, connect the mouse, change the current tension values (Va) or of the resistance respective of base (Rb) or of collettor (Rc).

At the end of every deviation, the programme recall the calculation subroutines (cited upon) to update the job points results (the points searched in the fig ).

For a good understanding, the programme draw also for the points the curves from where are obtained the job points, with the subroutines recall of the calculation for a regular series of the abscissa values, utiliser the loop instructions (For-Next).

Particularly interesting for the didactics aims, is the characteristic ic-Vc (a ib costante) visualization intersected from the cargo line: moving the cursors it can follow the curves variation picking some of these immediately the correlations (the speed of the actually calculators allow the update from the fig in real time).

Fig.2 Programme for the job points transistor determination, give Va (in Volt), Rb and Rc (in kOhm).