#Macspice tutorial how to

In the next article I'll add more complexity to the model more complicated and do more with the analysis of the circuit.This tutorial will teach you how to create a circuit schematic, perform a simulation, and view circuit waveforms in LTspice for Mac. The second displays the current supplied by the v1 supply, i(v1). The first print statement above displays the voltage at node 1, v(1), which is 9V as we would expect. The op command tells SPICE to analyze the operating point (steady state). You may wonder what the op, and print statements do. You can load it into MacSpice (or whatever SPICE program you use) and analyze it. So, create the file, example1.cir, and put the above text in it. Don't forget that or the component you put on the first line will be missing when SPICE analyzes the circuit! The first line of a SPICE file is always the title. * Capacitor in parallel on nodes 1 and 0, 100uF * Resistor in parallel on nodes 1 and 0, 1 ohm with a code (K, Meg, M, N, P, U, etc., respectively) so our 100♟ cap value is represented by 100U. Note that SPICE can represent kilo, mega, milli, nano, pico, micro, etc. (It has another option, the initial voltage, but we'll ignore that for now) The capacitor is described by Cname n+ n- value as you might expect.

Next, there's the 'motor' resistor described by Rname n+ n- value where value is the resistance, let's say 1Ω. A simple DC supply is described by Vname n+ n- value where n+ is the positive node, n- the negative node and value is the DC volts value. I spent about 2 hours trying to find out that I simply needed to number the ground node zero!! Note that the GND node must ALWAYS be node 0 or you will get errors like 'Warning: singular matrix', 'Warning: source stepping failed', 'Warning: gmin stepping failed', 'No convergence in DC analysis', and 'failed to converge'. Here's the circuit with the nodes labeled to make it easier to enter into a SPICE file. Let's start with a much simpler circuit we'll ditch both transistors and represent the motor as a simple resistor, tying it directly to 9V and GND. The description file lists each of the components, and what nodes the components are connected to. Then I have to convert that into a SPICE circuit description file. First I have to draw the old motor circuit. I found the following websites helpful, too: The MacSpice website has good documentation: I want to use modeling to analyze the existing circuit and to help me come up with a better design.īut first, let's talk about SPICE.

#Macspice tutorial driver

Revisiting Pokey's Fan Motor Circuit: You may recall the crappy, last minute, motor driver circuit I threw together for Pokey, my firefighting robot. The tool remains text based, but with some menu wrappers for a few functions. You can model numerous devices and print and plot the results of the simulation. It can do transient analysis, steady-state, AC small signal analysis, DC transfer function analysis. SPICE, Simulation Program with Integrated-Circuit Emphasis, has been around for 30+ years and is still an industry standard for modeling circuits to see how they'll behave.

#Macspice tutorial software

The last couple days I've been learning how to use SPICE circuit simulation software and thought I'd share what I've learned.