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This chapter covers a number of tutorials that will help you get started with SIMetrix.
Tutorial 1 is designed for total novices. You may wish to skip to tutorial 2 if you already have experience with SPICE type programs.
Tutorial 2 assumes you have grasped the basics of using the schematic editor. You don't have to worry about setting up analyses or the characteristics of any input stimulus such as V2 in tutorial 1; these procedures will be explained.
If you are an experienced circuit designer but have never used a circuit simulator before, we recommend you read Simulation for the Novice. This will familiarise you with a few concepts about simulation that may be alien to you if you are used to traditional methods of evaluating circuits.
On Windows the example files are first installed under the main installation root (e.g. under C:\ Program Files\ SIMetrix800\ support\ examples) but it is not intended that they are used from that location. Instead they will be copied to your "My Documents" folder when SIMetrix starts for the first time, but only if you accept the option to do so. If you can't find the examples files, you may need to manually copy them from the installation root to a suitable location of your choice.
In the following tutorial discussions, the examples directory is referred to as 'EXAMPLES'.
When measuring a real circuit, you would probably connect up a power source - bench power supply perhaps - maybe also some signal source, then switch it on and take measurements using - probably - an oscilloscope. You can also make adjustments to the circuit and see the effects straight away.
For simulation, you have a choice of analysis modes and not all of them have an exact real life equivalent. The analysis mode that most closely resembles the method of bench testing a circuit described above is transient analysis. This performs an analysis over a specified (by you) time period and saves all the results - i.e. all the voltages and currents in the circuit - to your hard disk. The difference between real life testing and simulation is that the simulation is not running all the time. If you want to see the effects of changing a part value, you have to change it then re-run the simulation. (But note there is a potentiometer device that automates this procedure see Potentiometer).
In order to solve the circuit, the simulator has to calculate the voltage at every node at every time point. Disk space is cheap and plentiful so SIMetrix saves all these values as well as the device currents. Not all simulators do this, some require you to state in advance what you want saved.
After the run is complete, you can then randomly probe the circuit to look at any voltage, current or device power over the analysis time period. You can also place fixed probes on the circuit before running the analysis which will cause the waveform at that point of the circuit to be automatically be displayed while the simulation is running or optionally after its completion.
Some of the other analysis modes are: AC analysis which performs a frequency sweep, DC sweep which ramps a voltage or current source and noise analysis which calculates total noise at a specified point and which parts are responsible for that noise.
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