## Re: [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations

 Re: [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations From: Felix Maier - 2011-10-01 08:15:24 ```2011/10/1 Sam Fentress : > Hi all, > > This is a really simple question I'm sure, but I can't work it out from the > documentation, nor from the examples, all of which have much more > complicated things than I'm trying to do. > > I simply want to create an AC circuit and see the sine wave of the voltage > in the circuit. For example, I'd like to create a simple series AC circuit > with a capacitor and see the sine wave before and after the cap. > > My sample circuit can be seen here: > https://skitch.com/samfentress/fh7s9/qucs-0.0.15. I made it a transient > simulation since I understand that's what I want if I want time-varying > results (i.e. a sine wave of voltage over time), and set it to go 0.05 s. > However, when I run "Simulate" it never ends. > > I'm obviously misunderstanding something. All the complicated transient > simulations that I downloaded work fine, so either I haven't set up the > simulation right or my circuit doesn't make sense. > > Any thought? Hello Sam, try to set the initial voltage of the capacitor to zero. This means the cap. has no charge at the beginning. > > Thank you, > Sam best regards Felix ```

 [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations From: Sam Fentress - 2011-09-30 22:01:27 ```Hi all, This is a really simple question I'm sure, but I can't work it out from the documentation, nor from the examples, all of which have much more complicated things than I'm trying to do. I simply want to create an AC circuit and see the sine wave of the voltage in the circuit. For example, I'd like to create a simple series AC circuit with a capacitor and see the sine wave before and after the cap. My sample circuit can be seen here: https://skitch.com/samfentress/fh7s9/qucs-0.0.15. I made it a transient simulation since I understand that's what I want if I want time-varying results (i.e. a sine wave of voltage over time), and set it to go 0.05 s. However, when I run "Simulate" it never ends. I'm obviously misunderstanding something. All the complicated transient simulations that I downloaded work fine, so either I haven't set up the simulation right or my circuit doesn't make sense. Any thought? Thank you, Sam PS: Apologies if this got sent twice. I sent this a moment before my registration went through yesterday, and it seems to be still waiting in the queue ```
 Re: [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations From: Felix Maier - 2011-10-01 08:15:24 ```2011/10/1 Sam Fentress : > Hi all, > > This is a really simple question I'm sure, but I can't work it out from the > documentation, nor from the examples, all of which have much more > complicated things than I'm trying to do. > > I simply want to create an AC circuit and see the sine wave of the voltage > in the circuit. For example, I'd like to create a simple series AC circuit > with a capacitor and see the sine wave before and after the cap. > > My sample circuit can be seen here: > https://skitch.com/samfentress/fh7s9/qucs-0.0.15. I made it a transient > simulation since I understand that's what I want if I want time-varying > results (i.e. a sine wave of voltage over time), and set it to go 0.05 s. > However, when I run "Simulate" it never ends. > > I'm obviously misunderstanding something. All the complicated transient > simulations that I downloaded work fine, so either I haven't set up the > simulation right or my circuit doesn't make sense. > > Any thought? Hello Sam, try to set the initial voltage of the capacitor to zero. This means the cap. has no charge at the beginning. > > Thank you, > Sam best regards Felix ```
 Re: [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations From: Sam Fentress - 2011-10-03 12:41:35 ```On Sat, Oct 1, 2011 at 4:15 AM, Felix Maier wrote: > 2011/10/1 Sam Fentress : > > Hi all, > > > > This is a really simple question I'm sure, but I can't work it out from > the > > documentation, nor from the examples, all of which have much more > > complicated things than I'm trying to do. > > > > I simply want to create an AC circuit and see the sine wave of the > voltage > > in the circuit. For example, I'd like to create a simple series AC > circuit > > with a capacitor and see the sine wave before and after the cap. > > > > My sample circuit can be seen here: > > https://skitch.com/samfentress/fh7s9/qucs-0.0.15. I made it a transient > > simulation since I understand that's what I want if I want time-varying > > results (i.e. a sine wave of voltage over time), and set it to go 0.05 s. > > However, when I run "Simulate" it never ends. > > > > I'm obviously misunderstanding something. All the complicated transient > > simulations that I downloaded work fine, so either I haven't set up the > > simulation right or my circuit doesn't make sense. > > > > Any thought? > > Hello Sam, try to set the initial voltage of the capacitor to zero. > This means the cap. has no charge at the beginning. > > Hi Felix, I tried that now (odd that it isn't set automatically), but it didn't help. My simulation still never ends. This is the output I see in the simulation window: Starting new simulation on Mon 03. Oct 2011 at 08:37:25 creating netlist... done. parsing netlist... checking netlist... netlist content 1 C instances 1 R instances 1 Vac instances 1 TR instances creating netlist... I don't see any errors or warnings. It seems odd that it's trying to create the netlist twice. Is this part of the problem, maybe? I've pasted my schematic below. Thanks, Sam ===== <.AC AC1 1 30 30 0 37 0 0 "lin" 1 "0 MHz" 1 "1 MHz" 1 "19" 1 "no" 0> <140 170 250 170 "Vin" 290 110 97 ""> <250 230 250 270 "Vout" 330 220 18 ""> <250 330 250 340 "" 0 0 0 ""> ```
 Re: [Qucs-help] Fwd: Beginner trying to understand AC/Transient simulations From: Eric - 2011-10-01 07:42:18 ```On 09/30/2011 03:00 PM, Sam Fentress wrote: > Hi all, > > This is a really simple question I'm sure, but I can't work it out from the > documentation, nor from the examples, all of which have much more > complicated things than I'm trying to do. > > I simply want to create an AC circuit and see the sine wave of the voltage > in the circuit. For example, I'd like to create a simple series AC circuit > with a capacitor and see the sine wave before and after the cap. > > My sample circuit can be seen here: > https://skitch.com/samfentress/fh7s9/qucs-0.0.15. I made it a transient > simulation since I understand that's what I want if I want time-varying > results (i.e. a sine wave of voltage over time), and set it to go 0.05 s. > However, when I run "Simulate" it never ends. > > I'm obviously misunderstanding something. All the complicated transient > simulations that I downloaded work fine, so either I haven't set up the > simulation right or my circuit doesn't make sense. > > Any thought? > > Thank you, > Sam > I am new at using QUCS so this may not be the answer you are looking for. I tried your circuit using the default values for the AC source and capacitor. QUCS was having a hard time computing the simulation and it may be because of the frequency of the AC source or the number of calculations required. I adjusted the values of the AC source to have a frequency of 1.0 MHz and changed the capacitor to a value of 1 nF and gave the Transient Analysis a stop time of 1 ms. When I plot the output I use a Cartesian graph graphing Vin.Vt and Vout.Vt. The graph gives good results. If this works, you can play around with the values to see how QUCS is working and hopefully get what you are looking for. Hope this helps you, Eric ```
 Re: [Qucs-help] Beginner trying to understand AC/Transient simulations From: Sam Fentress - 2011-10-03 13:05:26 ```> > I am new at using QUCS so this may not be the answer you are looking > for. I tried your circuit using the default values for the AC source > and capacitor. QUCS was having a hard time computing the simulation and > it may be because of the frequency of the AC source or the number of > calculations required. I adjusted the values of the AC source to have a > frequency of 1.0 MHz and changed the capacitor to a value of 1 nF and > gave the Transient Analysis a stop time of 1 ms. When I plot the > output I use a Cartesian graph graphing Vin.Vt and Vout.Vt. The graph > gives good results. If this works, you can play around with the values > to see how QUCS is working and hopefully get what you are looking for. > > Hope this helps you, > > Eric > > Hi Eric, Yes, that works! Boy, do I feel silly. I hadn't thought about the fact that the default settings for the power source was set at 1 GHz, and that this would be very time-consuming to simulate... With the AC power frequency dropped all the way down to 60 Hz, this simulation returned almost instantly. Thank you! Sam ```
 Re: [Qucs-help] Beginner trying to understand AC/Transient simulations From: Eric - 2011-10-04 03:58:12 ```On 10/03/2011 06:04 AM, Sam Fentress wrote: >> I am new at using QUCS so this may not be the answer you are looking >> for. I tried your circuit using the default values for the AC source >> and capacitor. QUCS was having a hard time computing the simulation and >> it may be because of the frequency of the AC source or the number of >> calculations required. I adjusted the values of the AC source to have a >> frequency of 1.0 MHz and changed the capacitor to a value of 1 nF and >> gave the Transient Analysis a stop time of 1 ms. When I plot the >> output I use a Cartesian graph graphing Vin.Vt and Vout.Vt. The graph >> gives good results. If this works, you can play around with the values >> to see how QUCS is working and hopefully get what you are looking for. >> >> Hope this helps you, >> >> Eric >> >> > Hi Eric, > > Yes, that works! Boy, do I feel silly. I hadn't thought about the fact that > the default settings for the power source was set at 1 GHz, and that this > would be very time-consuming to simulate... > > With the AC power frequency dropped all the way down to 60 Hz, this > simulation returned almost instantly. > > Thank you! > > Sam > ------------------------------------------------------------------------------ > All the data continuously generated in your IT infrastructure contains a > definitive record of customers, application performance, security > threats, fraudulent activity and more. Splunk takes this data and makes > sense of it. Business sense. IT sense. Common sense. > http://p.sf.net/sfu/splunk-d2dcopy1 > _______________________________________________ > Qucs-help mailing list > Qucs-help@... > https://lists.sourceforge.net/lists/listinfo/qucs-help > Your welcome, I am glad I could help. Eric ```