Questions tagged [ngspice]

Anything related to NGSPICE, an open-source SPICE simulation program.

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plot the max slopes of Voltage-Transfer characteristics in ngspice

I have implemented a basic CMOS inverter in ngspice, performing a DC sweep analysis on the input voltage to obtain the Voltage Transfer Curves (Vout vs Vin) at varying Vdd voltages. ...
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1answer
105 views

How do I model a simple metastable flip-flop in ngspice?

Problem I'm trying to simulate the simplest possible model for a flip-flop: two inverters connected in a circle. I'm using ngspice 31 on Arch Linux. I based my model on the CMOS SOI Inverter example (...
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1answer
102 views

Is it possible to pass netlist via command line to ngspice instead of using input file?

Is there a way to use ngspice command line without providing a circuit file? ex: passing the circuit as a string within the command line ? EDIT Currently the only way I could use ngspice in command ...
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61 views

Is it possible to plot Voltage vs Current in ngspice?

I need to plot the voltage in the Y axis and the current in the X axis in ngspice, like X-Y mode in an oscilloscope. I could not find anything regarding this in the manual. Can this be done? If so, ...
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0answers
95 views

dc sweep convergence issue for cmos inverter

I am having some convergence issue with DC sweep for a CMOS inverter. To duplicate the exact issue, see the following log as well as the attached netlist files, together with modelcard.nmos and ...
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0answers
145 views

ngspice .measure syntax in AC + par()

Why do the two netlists give totally different output impedance values ? Netlist 1: ...
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2answers
113 views

ngSpice Printing a lot of reference values instead of running the simulation

I have a project that uses ngSpice as a shared library. I fed a SPICE file to this project and the same file to ngSpice.exe. The ngSpice.exe finished execution within seconds however, the ...
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0answers
826 views

How to access parameter values in transient simulation and/or NGSPICE interactive interpreter

I want to make the time-step and stopping-time in a trasient simulation scale automatically by using the parameter values (.PARAM lines) in the netlist. Here is a minimal ngspice etlist to demonstrate ...
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0answers
7 views

setting an initial directory for the NGSPICE

After one launches NGSPICE, I want NGSPICE path, or current directory to be setup by me. How is that done? I.e., instead of (for example): ...
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0answers
9 views

Adding time dependence in xspice code models

I am looking for a way to define an xspice code models for a custom voltage source, in which the voltage can be varied as a function of time (for instance a time varying frequency sine wave). However ...
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1answer
37 views

Run Ngspice in batch mode or with python

For circuit simulations I have mostly been using LTSpice, where the netlist is generated automatically with a python script I ...
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0answers
49 views

Moving from LTspice to Ngspice

I wrote a python script that automatically generates and runs LTspice netlists. It runs perfectly on both Windows and Mac. Few ...
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0answers
12 views

Kicad bus pins in ngspice nelisting

In Kicad v5.1.9-1.fc32 release build, I have the following schematics. When netlisted for Ngspice, it provides the following netlist. ...
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0answers
21 views

How to achive Rser in a voltage in ngspice like in LTspice

I'd like to add Rser into my V1 like in the image below, but I couldn't find how to do it. I checked the internet, looked at ngspice's manual. I tried adding resistance next to V1 but PP value of out1 ...
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1answer
19 views

How to convert SIMetrix schematic into netlist

Is there a feature where the schematic created can be automatically converted to its netlist equivalent?
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1answer
105 views

modelling a fan in ngspice + KiCad

I'm using KiCad 5.1.7 and have created a simple circuit just to see what happens. It contains a fan, an unpolarized capacitor (110u) and a VSource. [Just wondering what happens..] When I try to ...
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1answer
23 views

Problem adding tranformer to QUCS schematic when simulating with ngspice

I'm having problems simulating the following circuit using ngspice alongside Qucs. The main problem I can see in log is that is acusing an singular matrix. I imagine the problem is related to how ...
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1answer
35 views

Printing the temperature of a device in ngspice?

I had a simple netlist down here: Example netlist v1 1 0 dc 15 r1 1 0 5k .end Yes, I could just calculate the power lost in here which yield about 45 mW. But the ...
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0answers
39 views

How to approximate the behavior of an inverse log potentiometer with ngspice?

I'm trying to write a Spice model able to approximate the behavior of an inverse log potentiometer, but cannot find the right formula to do it. What I have done so far: I have already written the ...
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1answer
54 views

adc_bridge in ngspice

Why does the adc_bridge not work when we have an input dc value? The plot for v(1) appears but v(cmp) is blank. ...
0
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1answer
72 views

What is the most straight-forward way to simulate this circuit?

I would like to verify the function of this circuit, as well as determine the power usage and heat generated by each component. (I need the latter for doing a thermal analysis) The circuit has been ...
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1answer
248 views

NgSpice error: unknown subckt

I am have defined a subcircuit header as: ...