(3) Add global parameters V and VG using the menu bar selection: PSpice -> Place Optimizer Parameter double click on the Optimizer Parameters construct and in the dialog type V in the Name field and press "Add", and then type VG, press, "Add" and then "OK". Sweep Type set to Linear and specify Start = 0, End = 14, Increment = 1.
Check checkbox Secondary Sweep, then also select Sweep Variable tab Global Paramater, and then type "VG" in Paramater Name. Sweep Type set to Linear and specify Start = 0, End = 400, Increment = 10. In Options, Primary Settings select Sweep Variable tab Global Paramater, and type "V" in Paramater Name. (2) Navigate the menubar: PSpice -> Edit Simulation Profile -> Analysis Type, and select DC Sweep. (1) Create a fresh project, and create this simple schematics by dropping parts from "Place"->"Part" dialog. To set up a new plate-curves project in PSPICE/ORCAD from scratch:
The project does a DC sweep over anode voltages, with secondary sweep, where the secondary sweep steps across grid voltage range.
I borrowed the following technique from The article that discussed the technique is in currently available only in Russian, hence I point directly to a zip file with a PSPICE project that computes plate curves.
How to Show Plate Curves, Loadlines and Max Dissipation Curves 3.1 Plate Curves There is probably no "best" setup, but for quick runs with precision sufficient for audio applications I use the following PSPICE setting for "Edit Simulation Profile", "Analysis Type": "Time Domain (Transient ):įor better precision I use slightly more dense steps - 5 or even 1 us.ģ. What is the best setup for tube transient analysis? Just because you entered some data in parametric sweep dialog box does not mean you're running a parametric sweep until you check the "Parametric Sweep" box!Ģ. I limit myself to 'K', and on rare occasions when I do need a 1M resistor I punch in "1000k" instead.ġ.5 Small assorted gotchas Parametric sweep checkbox. My "workaround" for this is in not using Mega-Ohms at all. Instead of typing 1M you must type 1Meg or 1meg. PSPICE is not case sensitive and it does not understands that 1M is not a 1m! In other words, your 1M pot or greed shunt or feedback resistor will be actually processed by SPICE as 1 milli-Ohm resistor, something infinitely close to a straight wire in the world of tube circuits. The circuit will suddenly start working in the most strange way. What is so special about that? 1M entered in PSPICE as a value for a resistor will ruin your day. The easiest solution is to connect one wire to the ground.ġM resistors were pretty popular as values of volume pots or grid resistors in old tube schematics and thus SPICE tube circuit modeling may need these. PSPICE, as well as most variants of SPICE will complain if the sub-circuit that is formed by the output taps of a tube output transformer and the load is disconnected from the main circuit. Instead, in the "New Project" dialog box which pops up after a name and directory selection dialog is done, I chose an option "Based On" and find a project which is a best prototype for a new design. Note that "NAME" need not be 0 if you want to have several grounds with different names, then you can change NAME from 0 to anything like G1 etc. Then you can cut and paste this node whenever you need a ground. In the popped-up dialog, select "Do not Display" and press "OK" button. By the way, "0" need not be displayed on the schematics page to hide, it double-click on the part - this will show the properties list, single-click on "NODENAME" and the press button "Display". After that I always do Ctrl-c, Ctrl-v on such node if I need an another one. To come up with such node, I created a grounding part using the parts menu (an icon will work, too), double-clicked on it to open its property dialog and then set its NAME and NODENAME properties to 0. I use a grounding-symbol node for this purpose. I believe a zero node is used as a reference point to calculate voltages and currents against. Zero Node and Other Assorted Oddities 1.1 A Zero NodeĪn otherwise healthy circuit will not work unless there is at least one node part named 0. Seamless SPICE Sync: Instant FOURIER output plotterġ. Collecting and Plotting Distortion Dataħ.
How to Show Plate Curves, Loadlines and Max Dissipation Curvesģ.4 Push-pull plate curves 4. What is the best setup for tube transient analysis?ģ. from scratch?ġ.5 Small assorted gotchas 2. Tube Simulation with PSPICE: Tips, Tricks, Techniques Tube Simulation with PSPICE: Tips, Tricks, TechniquesĪuthor: Dmitry Nizhegorodov My other projects and articlesĬopyright © 2001-2013 Dmitry Nizhegorodovġ.2 Starting a brand new project.