Questions tagged [qucs]

For questions about the Quite Universal Circuit Simulator (QUCS) open source circuit simulator package.

9 questions with no upvoted or accepted answers
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Qucs model for 2.4 GHz matching circuit

I am designing a matching circuit for an EFR32BG13 SoC. The current board layout looks like this: In addition to the visible layers (top and bottom), layer 2 is a solid ground plane and layer 3 is a ...
1
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1answer
37 views

Why is there no variation caused by this swept parameter?

I quite like Qucs now that I more or less have the hang of it. Unfortunately, I can't figure out how to get a parametric sweep working. I'm running an AC simulation on this circuit: For now I'm not ...
1
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1answer
563 views

Matching wideband antenna with QUCS

I am trying to match a dipole antenna to a 50Ω source. Problem is that for my frequencies (VHF) the complex impedance basically circles the 50Ω point between VSWR 2 and 3 lines. Because of that ...
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0answers
10 views

simulate a thyristor triggered load having a RC branch

In the following picture you have a simulation to figure out the voltage on a Thyristor triggered load. The current of triggering on the thyristor gate is 300 mA. What I am looking for is a signal on ...
0
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0answers
88 views

Trying to build a latch circuit on Qucs using BJT transistors. I can't find what is wrong

I seem to be able to get it to work on CircuitLab: simulate this circuit – Schematic created using CircuitLab However I can't, for the life of me, find a way to build the same thing on Qucs. I ...
0
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1answer
30 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 ...
0
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0answers
79 views

NFC Antenna matching

I am trying to follow the TI document on NFC antenna matching for the TFR7970A chipset. http://www.ti.com/lit/an/sloa241b/sloa241b.pdf I am under linux, and while I could try wine to use the smith ...
0
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2answers
285 views

QUCS Darlington pair

I'm modeling a Darlington pair in QUCS to understand better how to use it in practice. The model is below: The DC analysis predicts a current in the base of T1 of about 1uA and a collector current on ...
0
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1answer
644 views

How to setup a simulation on QUCS for a RF differential source?

I need to setup some simulations on QUCS for the RF circuit below: Pin1 is IC's positive port and Pin2 is IC's negative port. My initial goal is to investigate the circuit behavior on different ...