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CricuitMaker Student Software Flawed?
The last issue of QST had a short article on the CircuitMaker Student
edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen |
On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote:
The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Ed, I don't have any experience of CircuitMaker but I do have trouble with getting oscillators to oscillate on other simulation packages. This is inherent in the design of the simulators in that they will deliberately try to stabilise the circuit and stop the oscillation from taking off! If you have an option in there to 'skip initial transient solution' or something similar, it's good to check the box and bypass it - this is the thing that tries to DC stabilise the circuit. From there, it relies on noise to get the oscillator start and if there isn't any, it won't... -- Duncan Munro M0KGK http://amateur.duncanamps.com/ BOF #023 FISTS #10815 |
On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote:
The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Ed, I don't have any experience of CircuitMaker but I do have trouble with getting oscillators to oscillate on other simulation packages. This is inherent in the design of the simulators in that they will deliberately try to stabilise the circuit and stop the oscillation from taking off! If you have an option in there to 'skip initial transient solution' or something similar, it's good to check the box and bypass it - this is the thing that tries to DC stabilise the circuit. From there, it relies on noise to get the oscillator start and if there isn't any, it won't... -- Duncan Munro M0KGK http://amateur.duncanamps.com/ BOF #023 FISTS #10815 |
You need to set an "Initial Condition" (place the I.C. box from parts) for it
to begin oscillating :-) -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
You need to set an "Initial Condition" (place the I.C. box from parts) for it
to begin oscillating :-) -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
"Ed Bailen" wrote in message ... The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen Are you sure you set the simulation time long enough for the oscillator to get started ? |
"Ed Bailen" wrote in message ... The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen Are you sure you set the simulation time long enough for the oscillator to get started ? |
On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote:
The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Paul OH3LWR |
On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote:
The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Paul OH3LWR |
"Paul Keinanen" wrote in message
... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Injecting a pulse usually works with SPICE, I've found. Leon |
"Paul Keinanen" wrote in message
... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Injecting a pulse usually works with SPICE, I've found. Leon |
"Leon Heller" wrote in message ... "Paul Keinanen" wrote in message ... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. ... If the simulator does not simulate the thermal noise I do not believe this is necessary. The normal charge-up of any coupling caps will get you "off center" at the start. On PSpice ver 9 one of my students "couldn't get an oscillator to go". I lenghtend the simulation time and found that it took longer than he had set for the transient analysis. Out of the box on PSpice I got both a 555 and Colpitts to fly. I can't speak to CircuitMaker, but there may be analysis set-up parameters such as the aforementioned initial condition which may be the key. PSpice also has something about "skipping" an initial transient state/solution which I haven't experimented with to comment further, but could be a consideration. Watch the options... -- Steve N, K,9;d, c. i My email has no u's. |
"Leon Heller" wrote in message ... "Paul Keinanen" wrote in message ... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. ... If the simulator does not simulate the thermal noise I do not believe this is necessary. The normal charge-up of any coupling caps will get you "off center" at the start. On PSpice ver 9 one of my students "couldn't get an oscillator to go". I lenghtend the simulation time and found that it took longer than he had set for the transient analysis. Out of the box on PSpice I got both a 555 and Colpitts to fly. I can't speak to CircuitMaker, but there may be analysis set-up parameters such as the aforementioned initial condition which may be the key. PSpice also has something about "skipping" an initial transient state/solution which I haven't experimented with to comment further, but could be a consideration. Watch the options... -- Steve N, K,9;d, c. i My email has no u's. |
I have found that that generating a narrow pulse with a current source works
well for me. The oscillator gets going rather quickly because the narrow pulse has a wide frequency spectrum and since the ideal current source is an open it doesn't impact the circuit operation. Darrell VE6DWB "Paul Keinanen" wrote in message ... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Paul OH3LWR |
I have found that that generating a narrow pulse with a current source works
well for me. The oscillator gets going rather quickly because the narrow pulse has a wide frequency spectrum and since the ideal current source is an open it doesn't impact the circuit operation. Darrell VE6DWB "Paul Keinanen" wrote in message ... On Sun, 06 Jun 2004 17:59:00 -0500, Ed Bailen wrote: The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Typically, an oscillator is just a noise amplifier with some frequency selective feedback. In a real oscillator, there is always some wide band thermal noise present, which is amplified, some selected frequencies are circulated back to the input and reamplified and so on. Finally, there is going to be a narrow spectral line and a wide band noise floor due to the thermal noise, assuming of course that the phase, amplification and feedback loss conditions are correct. If the simulator does not simulate the thermal noise inherent in all resistors and semiconductors in temperatures above absolute zero, it is not very likely that the design would oscillate. Inject a very low level wide band noise into the amplifying stage and the oscillation should start. However, I have never seen the CircuitMaker or how to generate a wide band noise signal with it. Paul OH3LWR |
On Mon, 7 Jun 2004 17:21:03 -0500, "Steve Nosko"
wrote: Out of the box on PSpice I got both a 555 and Colpitts to fly. The 555 should start unconditionally, since it is based of the RC time constant and two comparator levels. Thus, it should not matter, what the initial charge in C is, since sooner or later one of the comparators will change state. A startup transient in the Colpitts may very well start the oscillation, since the transient is rich of harmonics and if one of the harmonics is connected back with sufficient gain through the frequency selective feedback, the oscillation should start. Paul OH3LWR |
On Mon, 7 Jun 2004 17:21:03 -0500, "Steve Nosko"
wrote: Out of the box on PSpice I got both a 555 and Colpitts to fly. The 555 should start unconditionally, since it is based of the RC time constant and two comparator levels. Thus, it should not matter, what the initial charge in C is, since sooner or later one of the comparators will change state. A startup transient in the Colpitts may very well start the oscillation, since the transient is rich of harmonics and if one of the harmonics is connected back with sufficient gain through the frequency selective feedback, the oscillation should start. Paul OH3LWR |
Hi,
Yes, I have tried doing just that, and it works after a fashion, but not always and not usually very well. The most recent ARRL handbook (2004) says that very special and expensive software is needed to simulate oscillators properly. 73 de k1jhj "Ed Bailen" wrote in message ... The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen |
Hi,
Yes, I have tried doing just that, and it works after a fashion, but not always and not usually very well. The most recent ARRL handbook (2004) says that very special and expensive software is needed to simulate oscillators properly. 73 de k1jhj "Ed Bailen" wrote in message ... The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen |
"Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen ===================================== Not good. I hope that you will notify ARRL (or have) about this. If there are serious deficiencies in the software (regardless of whether it is free or not), then possible users should be made aware of them. Thanks for letting me know, just in case I try to use it. Jack W8RAG |
"Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen ===================================== Not good. I hope that you will notify ARRL (or have) about this. If there are serious deficiencies in the software (regardless of whether it is free or not), then possible users should be made aware of them. Thanks for letting me know, just in case I try to use it. Jack W8RAG |
"Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen I have a Colpitts oscillator running ok in Circuit Maker Student V6.2c. I can send you the file if you'd like. (small, about 13 kb) |
"Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen I have a Colpitts oscillator running ok in Circuit Maker Student V6.2c. I can send you the file if you'd like. (small, about 13 kb) |
"John" wrote in message ... "Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen I have a Colpitts oscillator running ok in Circuit Maker Student V6.2c. I can send you the file if you'd like. (small, about 13 kb) I should add, there is one thing (at least) that you have to be aware of with CM. Wires that look like they are connected may not be. Use Simulation, Check Pin Connections. This should tell you any pins you think are connected but which CM thinks are not connected. |
"John" wrote in message ... "Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen I have a Colpitts oscillator running ok in Circuit Maker Student V6.2c. I can send you the file if you'd like. (small, about 13 kb) I should add, there is one thing (at least) that you have to be aware of with CM. Wires that look like they are connected may not be. Use Simulation, Check Pin Connections. This should tell you any pins you think are connected but which CM thinks are not connected. |
On Thu, 17 Jun 2004 04:13:42 +0100, "John"
wrote: "Ed Bailen" wrote in message .. . The last issue of QST had a short article on the CircuitMaker Student edition circuit design package. I downloaded it and spent several hours trying various oscillator designs (including the phase shift oscillator discussed in the same issue of QST). I couldn't get any of the designs to oscillate! I was mainly trying Colpitts oscillators. Has anyone else tried designing oscillatos with this application? Thanks, Ed Bailen I have a Colpitts oscillator running ok in Circuit Maker Student V6.2c. I can send you the file if you'd like. (small, about 13 kb) John, I'd like to take a look at your circuit if you wouldn't mind emailing it to me. Thanks. Thanks to the rest of you for advancing my education. Ed Bailen - N5KZW |
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