Data Sheet

LABCENTER ELECTRONICS LTD.
232
At the moment no trace is drawn for the current probe. Press the space bar to re-simulate the
graph, and the trace appears.
Even from the minimised graph, we can see that the current in the feedback loop follows closely
the wave form at the output, as you would expect for an op-amp. The current changes between
10mA and 0 at the high and low parts of the trace respectively. If you wish, the graph may be
maximised to examine the trace more closely.
Frequency Analysis
As well as transient analysis, there are several other analysis types available in analogue circuit
simulation. They are all used in much the same way, with graphs, probes and generators, but
they are all different variations on this theme. The next type of analysis that we shall consider is
Frequency analysis. In frequency analysis, the x-axis becomes frequency (on a logarithmic
scale), and both magnitude and phase of probed points may be displayed on the y-axes.
To perform a frequency analysis a Frequency graph is required. Click left on the Graph icon, to
re-display the list of graph types in the object selector, and click on the Frequency graph type.
Then place a graph on the schematic as before, dragging a box with the left mouse button.
There is no need to remove the existing transient graph, but you may wish to do so in order to
create some more space (right click and delete object from the resulting context menu).