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Re: Need spice model for IR TX and RX
...best* I can do Dhanabal:
?? <---data sheet ? <--SPICE and related modeling software at site W. Warren *(See if there is a usable model already in LTSPICE similar to those devices, then "substitute values", or ask around here for help with 'maybe a PSPICE model?? You could always send the manufacturer an email request.) |
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Re: Need help to design a transimpedance amplifier
This is the case when first creating a source of noise, and then heroically fighting with them.
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It is better not to use a charge pump to get negative voltage. You can build tranimpedansny amplifier of three transistors: common collector (npn), Common emitter (npn) and common collector (pnp). Three resistor and feedback resistor. Bordodynov. 04.08.2016, 13:46, "t.obulesu@... [LTspice]" <ltspice@...>: I have uploaded them with the name..New Microsoft PowerPoint Presentation(2).pdf and Noise.pdf here in files.. |
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Re: PWL TRIGGER syntax
Hi.
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Everything works. * D:\Program Files\LTC\LTspiceIV\Draft323.asc V1 x 0 PWL(0 0 1m 1 2m 1 3m 0) TRIGGER V(n003)>1 V2 n003 0 PULSE(0 2 0 10m 10m 0 20m) V3 y 0 TRIGGER V(n003)>1 PWL(0 0 1m 1 2m 1 3m 0) .tran 20m .backanno .end Bordodynov. 04.08.2016, 13:18, "tinix84@... [LTspice]" <ltspice@...>: does somebody have problem with this syntax? PWL (0 0 1m 1 2m 1 3m 0) TRIGGER V(n003)>1 |
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Re: Need help to design a transimpedance amplifier
Am 04 Aug 2016 00:31:30 -0700
schrieb "t.obulesu@... [LTspice]" <LTspice@...>: Let me say why am looking for new design..Hello t.obulesu, this is not the forum to discuss your circuit. Nevertheless, I'm stumbled about the following things, that might give you a hint you could thing about: Interpreting the image tek0000.png (red curve FFT) and in case I'm right, I can see a carrier at about 2.75Mhz with a spectrum of about n times ~300kHz width. This carrier may come from the SPI clock frequency. Furthermore I guess, the 300kHz might come via GND or VCC from the internal DAC oscillators, specified in the range from 250 to 340 kHz in the datasheet. Then, grounded on the fact, that the oscillators of the two DACs are not synchronised, their difference frequency is down-converted and will result as "noise" in the low kHz range. Check your PCB layout with respect to crosstalk paths and GND loops. Sorry for my broken English. -- Mit freundlichen Gr¨¹?en Kind Regards Peter Ragosch peter.ragosch@... |
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Re: Need help to design a transimpedance amplifier
Hi.
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The author of this opus (-Building of an optical lever system(1).pdf) or illiterate, or not very neat. Two schemes contain errors. While it may be disinformation. Bordodynov. 04.08.2016, 11:58, "t.obulesu@... [LTspice]" <ltspice@...>: Yahoo! Groups |
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Re: Input impedance of an energy saving fluorescent lamp (CFL) 21W
¿ªÔÆÌåÓýTo: ltspice@... From: LTspice@... Date: Tue, 2 Aug 2016 20:33:58 +0300 Subject: Re: [LTspice] Input impedance of an energy saving fluorescent lamp (CFL) 21W ?
http://ltwiki.org/?title=Components_Library_and_Circuits
CFL Circuit 13 Watt 120 VAC Compact Fluorescent Bordodynov. 02.08.2016, 19:04, "Jerry Lee Marcel jerryleemarcel@... [LTspice]" : > CFL's are very non-linear, in fact exhibit negative resistance. There are a few Spice models on the internet, you may have to adapt them for LTspice. > > Le 02/08/2016 ¨¤ 17:42, michael883575@... [LTspice] a ¨¦crit?: > >> I am attempting to simulate a loaded inverter using the equivalent input impedance of the CF lamp as the load. Is there anybody in the group who might have an idea as to what a typical value for example for a 21W lamp might be. >> >> Thank you very much in advance >> >> Michael > > ---------------------------------------- > > L'absence de virus dans ce courrier ¨¦lectronique a ¨¦t¨¦ v¨¦rifi¨¦e par le logiciel antivirus Avast. > www.avast.com > > |
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Re: Input impedance of an energy saving fluorescent lamp (CFL) 21W
¿ªÔÆÌåÓýHi Bordodynov and all who helped, Thank you very much for the link ?and the files for the 13W, 120V AC Compact Fluorescent lamp. Unfortunately, I was looking for a more representative power (20W or nearest and I was hoping to load up to at least 100W/VA) and 230V/240V AC 50Hz . ?I could see how to basically tweek the relevant parameters to achieve what I was looking for but I was not sure that the result would be well and truly representative. ?Besides, I discovered that I had some inherent design flaws in my inverter design which had hitherto been uncovered-- this was not the given model problem. ??After overcoming the inverter problems I found I had in my archives a ballast design from Phillips and some time ago I had written ?a spice based model for a CFL based on a paper published by Shefield University researchers. ?I have now been able to do ?an LTspice simulation for a 30W CFL( I am really looking to simulate the designed inverter output power of 500W/VA) I am still thinking about how to simulate for 500W/VA. ?Ideas most welcome Thanks a lot everbody for your contributions Michael To: ltspice@... From: LTspice@... Date: Tue, 2 Aug 2016 20:33:58 +0300 Subject: Re: [LTspice] Input impedance of an energy saving fluorescent lamp (CFL) 21W ?
http://ltwiki.org/?title=Components_Library_and_Circuits
CFL Circuit 13 Watt 120 VAC Compact Fluorescent Bordodynov. 02.08.2016, 19:04, "Jerry Lee Marcel jerryleemarcel@... [LTspice]" : > CFL's are very non-linear, in fact exhibit negative resistance. There are a few Spice models on the internet, you may have to adapt them for LTspice. > > Le 02/08/2016 ¨¤ 17:42, michael883575@... [LTspice] a ¨¦crit?: > >> I am attempting to simulate a loaded inverter using the equivalent input impedance of the CF lamp as the load. Is there anybody in the group who might have an idea as to what a typical value for example for a 21W lamp might be. >> >> Thank you very much in advance >> >> Michael > > ---------------------------------------- > > L'absence de virus dans ce courrier ¨¦lectronique a ¨¦t¨¦ v¨¦rifi¨¦e par le logiciel antivirus Avast. > www.avast.com > > |
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Re: Input impedance of an energy saving fluorescent lamp (CFL) 21W
¿ªÔÆÌåÓýHi Bordodynov and all who helped, Thank you very much for the link ?and the files for the 13W, 120V AC Compact Fluorescent lamp. Unfortunately, I was looking for a more representative power (20W or nearest and I was hoping to load up to at least 100W/VA) and 230V/240V AC 50Hz . ?I could see how to basically tweek the relevant parameters to achieve what I was looking for but I was not sure that the result would be well and truly representative. ?Besides, I discovered that I had some inherent design flaws in my inverter design which had hitherto been uncovered-- this was not the given model problem. ??After overcoming the inverter problems I found I had in my archives a ballast design from Phillips and some time ago I had written ?a spice based model for a CFL based on a paper published by Shefield University researchers. ?I have now been able to do ?an LTspice simulation for a 30W CFL( I am really looking to simulate the designed inverter output power of 500W/VA) I am still thinking about how to simulate for 500W/VA. ?Ideas most welcome Thanks a lot everbody for your contributions Michael To: ltspice@... From: LTspice@... Date: Tue, 2 Aug 2016 20:33:58 +0300 Subject: Re: [LTspice] Input impedance of an energy saving fluorescent lamp (CFL) 21W ?
http://ltwiki.org/?title=Components_Library_and_Circuits
CFL Circuit 13 Watt 120 VAC Compact Fluorescent Bordodynov. 02.08.2016, 19:04, "Jerry Lee Marcel jerryleemarcel@... [LTspice]" : > CFL's are very non-linear, in fact exhibit negative resistance. There are a few Spice models on the internet, you may have to adapt them for LTspice. > > Le 02/08/2016 ¨¤ 17:42, michael883575@... [LTspice] a ¨¦crit?: > >> I am attempting to simulate a loaded inverter using the equivalent input impedance of the CF lamp as the load. Is there anybody in the group who might have an idea as to what a typical value for example for a 21W lamp might be. >> >> Thank you very much in advance >> >> Michael > > ---------------------------------------- > > L'absence de virus dans ce courrier ¨¦lectronique a ¨¦t¨¦ v¨¦rifi¨¦e par le logiciel antivirus Avast. > www.avast.com > > |
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Re: LT1171 model: syncronization not working
To answer the OT question. The VN2222 was a fairly generic ~5 ohm,60V vfet by modern standards. Similar devices are things like the generic? 2N7000 series available from many vendors. So an sot23 substitute device would be an NSD7002A from fairchild or other generic vendors for example. The more modern part will have a much more detailed spec sheet than the supertex part. Taking a quick look at specs they look quite similar. If you know what specs are important to your application, there are likely better choices than the 2n7000 series. Tim |
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Re: Need help to design a transimpedance amplifier
¿ªÔÆÌåÓýCheck the datasheet for the OPA 2846: Vn=1.2nV/sqrtHz, In=2.8pA/sqrtHz that means the OSI (optimum source impedance) is 428 ohms. The 100k resistors in the non-inverting inputs alone introduce 88uV (@100kHz BW) What is the transducer's impedance? Le 04/08/2016 ¨¤ 09:31,
t.obulesu@... [LTspice] a ¨¦crit?:
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Re: Need help to design a transimpedance amplifier
John Woodgate
¿ªÔÆÌåÓýDON'T upload stuff anywhere but to the list web site. You can upload any sort of file to Files => Temp but big graphics files can go to Files => Big Files. ? With best wishes DESIGN IT IN! OOO ¨C Own Opinions Only J M Woodgate and Associates Rayleigh England ? Sylvae in aeternum manent. ? From: LTspice@... [mailto:LTspice@...]
Sent: Thursday, August 4, 2016 8:32 AM To: LTspice@... Subject: [LTspice] Re: Need help to design a transimpedance amplifier ? ? Let me say why am looking for new design.. |
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Re: Need help to design a transimpedance amplifier
Let me say why am looking for new design..
We are currently using the receiver module which has three stages: 1. Trans Impedance stage 2. High Pass filter (HPF) stage 3. Unity gain amplifier (just for inverting the output of the HPF) Well...we used LM2662 as a -5V supply.. Here on we could see the hell noise below 100kHz.. I couldn't get rid of this noise by using bypass caps..but I could just reduced it.. Yet there is a lot of noise all across the circuit ranging from few kHz to hundreds of MHz... are the links where I have uploaded couple of documents.. I really don't know what sort of noise it is and from where it is coming... |
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Re: Thyristor library
"I read that sentence is concluded there was a missing "n": as in
either -> neither (or possibly have -> haven't)." Hmmm. Good point. This forum is especially vulnerable to that because people here are from all over the world and English is not the preferred language for many. I love how cosmopolitan this group is. Andy |
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Re: Thyristor library
Andy wrote:
"Hassan wrote: "I have found either the .lib file or the symbol !!! " That is good." I read that sentence is concluded there was a missing "n": as in either -> neither (or possibly have -> haven't). The reason I figured that was because I have the same failing in my written English. It can be a serious business to miss out negatives in written English, so I always check, and even then I occasionally miss one.? Regards, Tony |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
Frank Mead wrote:
"The 2n918, 2n5179, and the 2n2857 are still alive and well in Mouser database... they are still used..." Indeed they are listed. But did you check the prices and availability? At ?4 each for a 2N918, nobody's going to design it into anything; these are for maintenance only - mostly for military, and Central Semi are not the original manufacturer. They buy rights to old devices when discontinued by their originators. They're obsolete in the same sense as KT66s. [Stands back and awaits flames. ?:-) ?] Regards, Tony ? |
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Re: LT1171 model: syncronization not working
Matt, I just looked at it, and it looks as if SOME of the LT1171's
switching pulses are synchronized with the Vc input pin. Those ones have a narrower pulsewidth than the ones around them. Maybe it doesn't sync to every input pulse? I can't get the datasheet (LTC's website seems to be down, or not accessible from this side of the continent right now). The pull-up on the Vc pin is interesting; makes me think that it is at least partly implemented in the SPICE model, but that's no guarantee that it is functional in the model. Andy |
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Tony Casey
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