Self-oscillator. Measurements tool

The dependencies provided in the form of charts need to be analyzed, including the constant calculation of the same numerical values, which is inconvenient and time-consuming to do visually. To facilitate this work, the Simulator includes the Measurements tool.

For a more illustrative example, let's consider the use of Measurements for the self oscillator circuit:

How does the oscillation frequency and bias voltage change, for example, for the transistor emitter, depending on the supply voltage of the circuit? To do this, set in the DC sweep not the global variable Vcc, but the supply voltage of the actual source V14, from 4V to 20V in steps of 1V and run the calculation:

You can see how the emitter potential of the transistor shifts from 1V to 7V as the supply voltage increases. At the same time, you can see how differently the self oscillator circuit is run. It is not convenient to calculate generation frequencies visually or with cursors. Measurements greatly simplify this task.

Using this group of plots, you also can, for example, receive the dependencies of the frequency and generating amplitude on the circuit supply voltage and build plots of these dependencies. For such tasks, the simulator includes a convenient tool called Measurements.

Go to the Measurements tab. In this tab, you can add and configure the measurements you are interested in with the name you want. In our case these are: FrequenciLastPoint and AVG.

The measurement result is saved in the Sim Data tab:

Now the calculated data can be represented in the form of plots of dependencies f0(V24) and AVG(V24) as follows:

• Select the row of measurements that you are interested in and click the Plot button;

• Next, in the dialog that opens, adjust the display parameters and click Create.

On the same plot, you can similarly arrange another dependency, assign windows (Plot Number) and scales (Axis Number).

There are plots of dependencies of generation frequency and emitter bias voltage of self oscillator circuit transistor:

You can see that the frequency is almost independent of the supply voltage, while the output voltage increases linearly from 1V to 6.5V as the supply voltage increases, when the supply voltage increases from 4V to 20V.