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Re: Need help in oscilation of UcD
Dave,
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I'm not sure what else is wrong but C6 and C8 are probably not correct. regards Robert --- In LTspice@..., raymond hui <rcch87@...> wrote:
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Re: Need help in oscilation of UcD
Raymond, I agree there is something wrong in the model of a UM10155 you uploaded to the Temp folder. For an input sine wave with a 1 volt peak amplitude the output amplitude should be approximately 46 volts peak to peak. Instead I was seeing a peak to peak output in the millivolt range. Just as troubling was the very low amplitude of the signals at the gates of the power MOSFETs. I will keep looking to see if I can find the problem and will post message is I find the source of the problem.
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Howard raymond hui wrote: Really appreciate for your willingness to help me. I had zip my schematic in UM10155_4.zip under temp. I had modified some of the model because I imported some of the model into LPspice. I still unable to make the amplifier oscillate . My Vout is a pulse wave which has the value variate from 16mv to 33mv. My pwm waveform is also very strange. |
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Re: search problems
--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
Hello, OK, now I see the problem. Clicking on "Next" gives no results. It looks like Yahoo has broken again the search-function. The problem started 10 months ago. One couldn't search in newer messages for a couple of months. Then it was partly working again, but now it's function is again questionable. It looks for me that Yahoo can never can fix their problems with the search function in the Yahoo groups. I guess they have a big problem with the software management of the groups' messages. Maybe a wrong software architecture. Best regards, Helmut |
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Re: floating nodes multiplying
--- In LTspice@..., "gandolfreefer" <synchronousmosfet@...> wrote:
Hello Charlie, I just checked your uploaded circuit Pre_Amp_Rev_C_1.asc and have got no error message. There is only one overdue ".ends". You should delete it. It's at teh end of .model DN2540 ... .... .ends A .model never has an ".ends". You have to delete it. The simulation runs. What's the problem? Best regards, Helmut |
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Re: floating nodes multiplying
Thanks, Jim, I'll check and try that.
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I think the nodes are all cathode follower output nodes, and the DC path to ground is complicated for the output part because it is two triodes stacked. later. best, charlie -----Original Message-----
From: wagnerj@... Sent: Wednesday, November 25, 2009 2:27pm To: LTspice@... Subject: Re: [LTspice] floating nodes multiplying Hi,Charlie - Do all of those nodes have a DC path to ground? If not, then add a resistor to ground. It can be really large (10MEG, 100MEG, for example). Jim Wagner Oregon Research Electronics [Non-text portions of this message have been removed] |
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Re: Simulation of RS-latch: how to set gate prop delays and latch initital state.
--- In LTspice@..., Ed Lipiansky <lipiansky@...> wrote:
Hello Ed, Please take a look to this example in our Files section. Files > Examples > Educational > Digital Latch Other examples are here. Files > Examples > Apps > NorLch1.asc Files > Attached files sorted by message number > msg_14540 Best regards, Helmut |
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Re: floating nodes multiplying
Hi,Charlie - Do all of those nodes have a DC path to ground? If not, then add a resistor to ground. It can be really large (10MEG, 100MEG, for example). Jim Wagner Oregon Research Electronics |
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floating nodes multiplying
gandolfreefer
Hi,
getting floating node error messages for tube circuit...will upload and name "mikes_12ax7_preamp_node_problem" I have searched and searched, rebuilt schematic, renamed nets, and I can't figure out why ltspice keeps giving floating nodes error messaging. The voltages are correct and the fouriers appear valid, so the simulation appears to be working, but the floating nodes appear to be multiplying!! Before there were two, now there are four.... ???? thanks. best, charlie |
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Re: Anyone else getting messages like this?
chuck...
I treat them as hacking attempts to hijack and exploit the browser. Then I
hit Delete after blocking the sender... _____ From: LTspice@... [mailto:LTspice@...] On Behalf Of Alan B. Pearce Sent: Wednesday, November 25, 2009 7:57 AM To: LTspice@... Subject: Re: [LTspice] Anyone else getting messages like this? When I get those emails with base-64 encoded gibberish withinNo, I only get them from Yahoo Groups. There are about three I am on that are reasonably active with emails most days, and they all produce the effect. I figure it is down the gibberish at the start of the first bit I quoted - note that the hex characters go for a long way in one long line (on the copy I received back it had been folded into two lines) and I think that is what is confusing things. |
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Re: Need help in oscilation of UcD
raymond hui
--- On Thu, 11/26/09, Dave Allen <cdcat001@...> wrote:
From: Dave Allen <cdcat001@...> Subject: Re: [LTspice] Need help in oscilation of UcD To: LTspice@... Date: Thursday, November 26, 2009, 1:07 AM ? >Hi Dave, Did you modified any of the resistance and capacitance value in the UM10155? What is the Vin for your simulation? What value that you gained in the Vout ? >Thanks a lot for your information. Best Regards, Raymond Hi Raymond, Vin is set at 1.8v 1Khz out is 48v peak to peak approx with 30-0-30v power. I haven't checked this is the correct gain figure as I only modeled it out of curiosity. You did remember the enable link between J3 and J4 and a 4R load between J10 and J11 ? Having checked again the tran only settles around 50ms and takes an age to get there. There's a little of the switching waveform at the output - much more before the output choke! I haven't downloaded your version to check, but I can upload mine, such as it is. Sorry, won't be today though. Regards Dave Hi Dave,The J3 and J4 is? grounded in my schematic. Is it correct? Yes. I connected J3 and J4 with a 4 ohm resistor.? When you can upload your version ? I would like to have a look on how it simulate? Many Thanks,Raymond [Non-text portions of this message have been removed] |
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Re: Need help in oscilation of UcD
Hi Dave, Did you modified any of the resistance and capacitance value in the Best Regards,Hi Raymond, Vin is set at 1.8v 1Khz out is 48v peak to peak approx with 30-0-30v power. I haven't checked this is the correct gain figure as I only modeled it out of curiosity. You did remember the enable link between J3 and J4 and a 4R load between J10 and J11 ? Having checked again the tran only settles around 50ms and takes an age to get there. There's a little of the switching waveform at the output - much more before the output choke! I haven't downloaded your version to check, but I can upload mine, such as it is. Sorry, won't be today though. Regards Dave ---------- No virus found in this outgoing message. Checked by AVG - www.avg.com Version: 9.0.709 / Virus Database: 270.14.81/2524 - Release Date: 11/24/09 19:37:00 |
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Re: search problems
It is the same for me...
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Franck --- In LTspice@..., "Reinhard" <compfox@...> wrote:
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Re: Antenna preamp modeling
Howie, Brian (SELEX GALILEO, UK)
-> Have a look at GAASFET_PREAMP_2.asc in the temp directory to getyou going. I can't remember where it came from.The source of the circuit is To get realistic noise figures , inductor skin resistance and capacitor dielectric losses should be estimated and included. Brian SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 *** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. *** |
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Simulation of RS-latch: how to set gate prop delays and latch initital state.
Hello LTSpicers,
?? I would like to simulate an RS-latch. Simply two cross-coupled NOR gates. I excite them with a?two pulses into their?R and S inputs. I know how to do this. ? 1) What I am asking is how do I set-up the initial state? of the RS-latch? ?Example I want Q to? be 1 and Q_bar to be 0. ?2) How do I set up a specific gate prop delay for each? NOR gate? ?? Thank you. ?Ed- [Non-text portions of this message have been removed] |
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Re: Anyone else getting messages like this?
When I get those emails with base-64 encoded gibberish withinNo, I only get them from Yahoo Groups. There are about three I am on that are reasonably active with emails most days, and they all produce the effect. I figure it is down the gibberish at the start of the first bit I quoted - note that the hex characters go for a long way in one long line (on the copy I received back it had been folded into two lines) and I think that is what is confusing things. |
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Re: simpler frequency doubler circuit
Many thanks Philip for your valuable tips! I would have never got it for the LT1011 output pins!!! I got it working now!
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Franck --- In LTspice@..., Philip Bellingham <rmhc78a@...> wrote:
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Re: Damped Pseudo-Transient Analysis
Emma,
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? From the Help file: ? "There is no guarantee that the operating point of a general nonlinear circuit can be found with successive linear approximations as is done in Newton-Raphson iteration. Should direct Newton iteration fail, LTspice tries a number of other methods to find an operating point. Below is a table of the methods used and the options settings required to disable a particular method. ? Method Directive to disble Direct Newton Iteration .options NoOpIter Adaptive Gmin Stepping .options GminSteps=0 Adaptive Source Stepping .options SrcSteps=0 Pseudo Transient .options pTranTau=0 " ? ? - Philip --- On Wed, 11/25/09, Emma <smulan_emma@...> wrote:
From: Emma <smulan_emma@...> Subject: [LTspice] Damped Pseudo-Transient Analysis To: LTspice@... Date: Wednesday, November 25, 2009, 8:20 AM ? Hi everyone, What is meant with "Damped Pseudo-Transient Analysis"? Kind Regards, Emma [Non-text portions of this message have been removed] |
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Re: Need help in oscilation of UcD
raymond hui
Hi Dave,
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Did you modified any of the resistance and capacitance value in the UM10155? What is the Vin for your simulation? What value that you gained in the Vout ? Thanks a lot for your information. Best Regards, Raymond --- On Wed, 11/25/09, Dave Allen <cdcat001@...> wrote:
From: Dave Allen <cdcat001@...> Subject: Re: [LTspice] Need help in oscilation of UcD To: LTspice@... Date: Wednesday, November 25, 2009, 4:20 PM ? >Really appreciate for your willingness to help me. I had zip my schematic in UM10155_4.zip under temp. I had modified some of the model because I imported some of the model into LPspice. I still unable to make the amplifier oscillate . My Vout is a pulse wave which has the value variate from 16mv to 33mv. My pwm waveform is also very strange. Many Thanks, Raymond Hi Raymond, I modelled the UM10155 from the datasheet - the tran waveform does start off as a smallish squarewave then settles into a nice sine wave after 20-30ms using the tran command below: .tran 0 100m 0 1u startup uic I didn't find a model for the output devices or one of the diodes, but otherwise my circuit is as the datasheet. Regards Dave ---------- No virus found in this outgoing message. Checked by AVG - www.avg.com Version: 9.0.709 / Virus Database: 270.14.81/2524 - Release Date: 11/24/09 19:37:00 [Non-text portions of this message have been removed] |
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Re: Anyone else getting messages like this?
I get emails like that too, from time to time.
The gibberish is usually in "base-64" encoding, which is normally used as a way to encode binary data into non-binary text where it can be emailed. Usually you don't see it that way because the header and other stuff in the email message have the right information to tell your email reader that it is in base-64 and needs to be decoded. I think you occasionally see messages displayed like that because the sender's email lacks some of the required tags that are supposed to be there to identify it as base-64. Some email readers recognize it anyway and do decode it (so they look normal), but others do not. Oops - I just noticed you are seeing these blocks within the email header itself. That is something I haven't seen, which is to say I never saw it on those occasions when I looked at the headers. It might explain why your subject line appears blank; your email reader may stop interpreting the header at that point. When I get those emails with base-64 encoded gibberish within the emails, most of them are on another email group to which I belong, not a Yahoogroup, and I think don't come from Yahoo mail either. But what I've seen might be different than what you described. Andy |
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Re: simpler frequency doubler circuit
Franck,
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? Several things: ? 1. Your negative power supply voltage (V2) is in backwards so it is actually +15V at the LT1011 pin, not -15V. 2. The output transistor of the LT1011 is a floating transistor, the collector appearing at the pin referred to as the output and the emitter appearing at the pin referred to as ground. Probably not the best way to designate these pins. Look at page 10 of the LTC data sheet for the LT1011 for a typical application of a circuit that drives a load that is referenced to ground. ? 3. The RC filter that I believe you are using for a time delay also attenuates the applied sine wave such that the signal at the inverting input never crosses the threshold that you have set at the non-inverting input. ? ?? - Philip --- On Wed, 11/25/09, franck_borde <franck_borde@...> wrote:
From: franck_borde <franck_borde@...> Subject: [LTspice] simpler frequency doubler circuit To: LTspice@... Date: Wednesday, November 25, 2009, 8:35 AM ? Hello guys, Once again I would need your lights since I might be something stupid¡Really, I have implemented a very simple circuit with a LT1011 comparator and a XOR gate to create a frequency doubler circuit. Unfortunately, for some reasons the inputs to the comparator are both fixed to 14.2 volts (I should see 2.5V signal on the positive pin and a 5V at 1MHz on the negative pin). This 14.2V is somehow related to the bias voltage but I am not too sure how. It works when I directly drive the input pins with a voltage source so I am not too what is going on. Any ideas are welcome. I have downloaded the file in the temp folder (doubler_circuit. sch). Best regards, Franck |
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