Real electronic component
Replacement of ideal component models with real ones.
All previous calculations were done based on an idealized transistor. Now let's replace the ideal transistor with a real one, for example BC846. To do this, create a folder LIB PSPICE in the project folder and put there the file with PSPICE description of this transistor. (There are also a few more files describing other transistors).
Then change the transistor from the Simulation Generic Components library (supplied with the simulator by default) to any real transistor from the Miscellaneous Devices.IntLib library, for example 2N3904. Then in the Parameters region of transistor’s Properties panel, go to the Simulation field:
The Sim Model dialog will open:
On the left side of the dialog, in the Model Properties region, specify the location of the LIB PSPICE folder with the PSPICE file of the BC846 transistor. (In the future, as Altium Designer develops, it will be possible to connect mathematical models of real electronic components from different databases: Library, Server, Octopart).
In the Pin Mapping region of the dialog, check that pins of the transistor’s schematic symbol and its simulation model are matched correctly.
On the right side of the dialog, in the Model Description region, you can see values of the model mathematical elements, as well as the text of the connected model file.
If the model is connected unsuccessfully, a symbol (red square) appears at the bottom of the dialog.
The described principle of adding models of real electronic components is true for any other types of electronic components. After finishing your work with the Sim Model dialog, click OK. As a result, the BC846 transistor with a mathematical description will be taken into account in the circuit, which is closest to the real one.
Add an expression to calculate the phase-frequency characteristic. Also add an additional ordinate axis in the settings.
Now run the AFC and phase-frequency characteristic calculation with the real BC846 transistor and the 10µF separating capacitor.
As you can see from the plot, the amplifying properties of the circuit with the real BC846 transistor start to decrease above 10 MHz.
