7/10/2023 0 Comments Macspice cannot see the plot linesYou may be able to do this with an AC simulation, but a transient simulation with different frequencies should give the result you are looking for. This will give you a current phasor, which can then be used to solve for a value of Z. Measure the amplitude of the current, and the phase difference between the voltage and current waveform. Calculate resistance in the same method as the first technique.ĪC Impedance: Superimpose a small (1 uV) sine wave on the port you want to measure. Apply a voltage source to the node you want to measure, and sweep the DC voltage over the range of expected node voltages. Output impedance (or some other port): Apply the required bias voltages to the inputs to cause the device to be at its quiescent point. R = 1/(Iin dI/dV)Įxplained, this is the inverse of the derivative of the input source's current w.r.t. Note that it is very possible to not have a flat curve. Use the equation below to give you the input resistance. Sweep the input DC voltage source over the voltage range you expect to use the circuit. I havent looked at this in detail, but a glance shows one obvious problem with the code which explains the reason for error. If any output loading, power supplies, or additional biasing is required, include this in the schematic as well. Measuring input impedance: Apply a DC voltage source to the input of your circuit. They work regardless of whether you are looking at the input or output. The first deals with DC impedance, and the second deals with AC impedance. You can follow any responses to this entry through the RSS 2.0 feed.īoth comments and pings are currently closed.I know of two methods for impedance measurement. On Wednesday, February 18th, 2015 at 7:10 am and is filed under Everything Else, Open Source Software. It really is amazing what these tools can do, and they continue to bring a smile to my face. However, now I cant find the original language in the source code or. Warning: Source 'vin' has no DC value specified, 0V assumed. Hi, the article states The original SPICE program was released under a restrictive license. I can start with this very simple LPF circuit: Four double-pole, low-pass, LC-filtersĪnd then in the MacSpice console: MacSpice 1 -> source lpf.cktĬircuit: Four double-pole, low-pass, LC-filters In fact, I'm sure my retina MacBook Pro is probably more powerful than all the computers the EE Dept. In the subsequent years, MacSpice is around, and it's got all the models, and all the capabilities that the old SPICE had - plus some amazing plotting. And of course, that was a good 30 years ago. yes, let's just say they were some very Good Times. These are tools that I just can't ever forget, and all the time I spent on the terminals in the Terminal Rooms in the EE building. I have the following codes: fig, ax plt.subplots() expiryrange 180, 360, 540, 720. This means that, first you have to use the function plot () to create an empty graph and then use the function lines () to add lines. However, it can be used to add lines () on an existing graph. This is the SPICE circuit netlist file that is used as the basis for all SPICE circuit simulations. Note that the function lines () can not produce a plot on its own. You can see this by adding a line format spec that includes a marker to your plot command. A new window will appear with the title of . Therefore, your code plots a single point at each t value, but they are not connected. Every now and then I remember all the work I did in college, and at Auburn University with SPICE and MAGIC. I am using an online backtesting platform Quantconnect which use jupyter as their research environment. Right-click in a blank area within the schematic window and select View > SPICE Netlist from the contextual menu.
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