03-18-2007 08:15 PM
03-19-2007 10:24 AM
I am going to reply to this question, but be warned that my views are only my views.
I am assuming that you are referring to the schematic symbol used for the 555 timer. The way it is arranged now is the accepted norm for most schematic representations of that IC and is not aligned with the the datasheet pin-out physically. It is arranged like this to make the schermatic entry and readability better. It used to be arranged just like the pin-out diagram in older version of EWB and it was really messy when wiring it up and it looked horrible. In my opinion, it is the way it should be. You could always create a symbol to your liking and just copy the model to it if you prefer a different presentation for this IC.
The second part of your quest has been aswered in a previous post, but I will answer it again. Multisim does not simulate in "real time". You can speed it up by adjusting the TMAX option under Simulation-Default Instrument Tab, but that will only go so far before errors will pop up. The time shown at the bottom of the screen represents "simulation time" or what I like to call "equivalent real circuit time". This represent what the real circuit timing would be if you would build your circuit on a breadboard and test it. Like you said in your post, it may take 10 seconds of "real time" to simulate 1 second of "circuit time". This is something that is inherent with using transient simulation with Multisim and the instrument packages. It just takes the simulator time process all the nodes, waveforms, voltages and run them through the Spice Engine to come up with a solution for your circuit.
To take this further, if you need immediate results and don't want to wait then you should try setting up the analysis using the Grapher. Using the Grapher you set your type of analysis, select your plot points and usually have more of an instantaneous result. and it gives the results just like what you would view on the O-scope. You bypass the instruments when you do this and I believe that frees up processor time to devote more to the circuit calucation thereby renderering faster results ( this is my theory about why it goes faster using this technique and may not be the only reason it is faster)
I hope this helps and is not too confusing. It just take a little time getting used to the way Multisim does things, but after you get accustomed to it and its little quirks, it really is a great simulator.
03-19-2007 10:32 AM
03-19-2007 03:47 PM
03-19-2007 03:58 PM
03-20-2007 09:32 PM
03-27-2007 11:12 AM
04-01-2007 09:46 PM
04-02-2007 01:55 PM
04-04-2007 09:06 PM
so what good is this product if it cant even do simple/basic 555 stuff ??? i wouldn't be so upset over it if there were some patches or something i could apply to fix this issue (and who knows how many other issues).