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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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Re: LT1171 model: syncronization not working
¿ªÔÆÌåÓýOn many of the LT switch mode controllers, the sync function is not implemented in the spice model. Don¡¯t know about that specific one.Jim ' James Wagner Oregon Research Electronics
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"4 GROUP.zip" upload
Jeff (kinarfi) uploaded a file "4 GROUP.zip" to the group's Temp
folder, but there is no message yet to the group about it. I don't know if you forgot to send one, or if it is just held up by today's unreasonably slow Yahoo computers. Your upload says "WHAT AM I DOING WRONG WITH MY BS250P BS170". I think your keyboard's Caps-lock key is stuck. Either that, or you are shouting. Here is what's wrong. Problem 1: When you created your custom NMOS and PMOS symbols, you put the transistor name in too many places. In the Attributes, you have SpiceModel = BS250P Value = BS250P Doing that, causes the transistor to go into the SPICE Netlist like this: U1 OUT-1 N002 N001 BS250P BS250P Note that BS250P appears twice. It must be only once. Remedy: Edit the two symbols. Remove the SpiceModel attribute (leave it blank). Problem 2: You set the Prefix to "U". The U prefix is for lossy RC transmission lines, but your models are subcircuits. Remedy: Edit the two symbols. Change Prefix from U to X. After saving both symbols, close and re-open the schematics. Problem 3: Draft2.asc doesn't work because LTspice doesn't have a 2N7000 model in its library. But it has the 2N7002, which is similar. Regards, Andy |
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Re: Thyristor library
(Another reply that vanished into the Internet):
Hassan wrote: "I have found either the .lib file or the symbol !!! " That is good. The first thing to understand is that they are almost completely independent of one another. A symbol is just an icon, nothing more. LTspice has some of the symbols already. In the Select Component (F2) menu, choose the [Misc] area, then you can find DIAC, SCR, and TRIAC symbols. If you found .lib files, then you found their SPICE models. Now all you need to do is: (A) include the .lib file in your simulation, and (B) associate the symbol with the model inside the library file. To include the .lib file, first put the .lib file in the same folder with your schematic that uses it. Then add this as a SPICE Directive on your schematic: .lib filename.lib To associate the symbol with the model: Right-click on the symbol body and make sure Prefix is set to X. Open the .lib file in a text editor (such as Wordpad) to see what's inside it. There should be a subcircuit definition for the part you want to use. Scroll down until you find it. It might look something like this: .SUBCKT 2N6071B MT2 G MT1 Now you know the actual name of the model: 2N6071B. And you know the order of the pins: MT2, G, MT1. There could be several .SUBCKTs in the same file, each for a different part. Find the one you want. Go back to your schematic. Edit the name next to the symbol, and change it from "TRIAC" (or "SCR" or "DIAC"), to the name of the subcircuit you want to use ("2N6071B" in this case). The tricky part is to make sure the order of pins is correct. For a Triac, LTspice assumes the order of pins is MT2, G, MT1. If the order differs from that, then you should edit the .lib file and change the pins in the above .SUBCKT line to make them in that order. This may take a little effort to understand what the pins are, when they don't have those specific names. Regards, Andy |
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Re: Current Dependent Voltage Source
Wow, emails to [LTspice] are not making it again!
Here is a message I sent several hours ago that hasn't shown up yet: --- "rmoreno.phone" asked how to enter a table of measured values for her/his CCVS. Vlad might have had the table descriptions a little bit confused with respect to your question, because I think the data you have is voltage/current values, not voltage/time values. You wanted a controlled or dependent source, not an independent source. Using SPICE's built-in H element (current controlled voltage source or CCVS), LTspice *MIGHT* have the ability to accept a table of current/voltage values. See the Help pages for E (VCVS) and G (VCCS) elements. A table is listed as an option. "A look-up table is used to specify the transfer function." The same 'table' description is not listed for the F (CCCS) and H (CCVS) elements. I am not sure if that was an omission on those Help pages, or if that option really doesn't exist for those two controlled sources. The "LTwiki" (www.ltwiki.org) is where I usually go when I have questions about the Help pages. Unfortunately, the LTwiki also doesn't show a table option for the CCVS. That leads me to believe that you can't use a table with the standard CCVS element. But LTspice's B-elements can do that and much more. Here is from the Help page for B-elements: table(x,a,b,c,d,...) Interpolate a value for x based on a look up table given as a set of pairs of points. Start with a Bv symbol, then right-click on "V=F(...)" and edit it. I think (but could be wrong) it should look like this when you are done: V=Table( I(V4), 0mA, 0V, 1mA, 1mV, 2mA, 1.9mV, 3mA, 2.5mV ...) where I(V4) means the current measured through V4 (this is your controlling current), and the pairs that come next, are the (current, voltage) pairs that you measured. I have rarely used the Table() functions in LTspice, so please excuse my inexperience with them. Regards, Andy |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
Frank Mead
The 2n918, 2n5179, and the 2n2857 are still alive and well in Mouser database... they are still used... On Wed, Aug 3, 2016 at 4:26 PM, tony@... [LTspice] <LTspice@...> wrote:
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Tony Casey
aurvii
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