Do commoners have the same per long rest healing factors? LTSPICE #10: Trick For Finding The Input Impedance 2,457 views Nov 16, 2020 36 Dislike Share trevortjes 2.35K subscribers In this video I show a trick on how to find the input impedance of. how can i measure the Zin e Zout impedance in a circuit, with LTSpice?Input impedance: Put a zero-voltage generator in series with the input. Do you intend for it to be part of your circuit or as a measuring device . rev2022.11.15.43034. 3) Ran the AC analysis and plotted the output voltage V(vout). Step 1: How to Set Up the Simulation. . How can I attach Harbor Freight blue puck lights to mountain bike for front lights? I am a beginner to LTSpice, I make this simple netlist: I am using a test voltage source( 0 volts source) to calculate current through R2. In a message dated 6/20/2010 9:06:54 AM Central Daylight Time. .TF just doesn't seem to work in the expected way for the output impedance calculation when current is measured. Thanks, Why did The Bahamas vote in favour of Russia on the UN resolution for Ukraine reparations? (Its quite common to add a 0V source when you need to measure the current in a wire and there's no convenient single component to measure the current through.) If you choose 1 Ampere then the complex voltage is identical to the complex impedance (X=V/I). Stack Overflow for Teams is moving to its own domain! Note that the 3 dB rolloff (solid line) occurs about 16 MHz; way too high to help at 500 kHz. Finding about native token of a parachain. Thanks for contributing an answer to Electrical Engineering Stack Exchange! Output impedance: Do you mean the source impedance of the output signals or the load impedance? After running AC analysis, add trace V(OUTNODE)/I(CSNAME). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The output impedance parameter, Zo, is defined as the frequency dependent small signal impedance that is placed in series with an ideal amplifier and the output terminal in a closed loop configuration. --- In LTspice@, Dan K9WEK, hopperdhh@ wrote: In message , dated Sun, 20 Jun 2010, analogspiceman writes: --- In LTspice@, John Woodgate wrote: In a message dated 6/20/2010 7:00:48 AM Central Daylight Time. When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com. Jim said: I'm wondering what method folks here use to measure amplifier output. 23,613. This is a more complex question than it appears. To do this its very simple the first step is to make your desired circuit (I will do another instructable on how to actually do this) but leave the voltage source blank. Simpler to short the output through a 0V voltage source to ground, do another .op and divide Vthevenin by the current through the short. Would drinking normal saline help with hydration? However, here we document some of them because of their general interest. E Updated: another image. For example, I'd like to plot output power through R1 vs frequency for the following circuit. A Free & Open Forum For Electronics Enthusiasts & Professionals, Login with username, password and session length. On page 5, it say "FET (IRF510)'s gate impedance is 14-j26", which I should match impedance to my driver output. However, I am confused how to measure IRF510's gate input impedance, for example, in LTspice. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features Press Copyright Contact us Creators . compensation. I looked at the file on o/p Z for a current mirror but there you have two outputs to pick off. 4) Clicked (right) on the Y-axis and selected 'Linear'. In this video, you will learn how to measure the input and the output impedance of any circuit using LTSpice Doesnt sound so simple - nothing is I suppose. The next step is to right click on the voltage source and select advanced you will see several options and on the right there will be . The circuit is supposed to convert a 23 + 13j source impedance to a 50-ohm output impedance. To learn more, see our tips on writing great answers. I can specify the 23-ohm resistance of the source, but wasn't sure how to specify that L2 i= 13 / (2 * pi * frequency). Like AC stability analysis. I have searched DIY audio for a while and only found answers that aren't right. How to plot output impedance of a circuit kungfu_phil #82507 . I was clicking around LTSpice while reading up on Thevenin equivalent circuits and was wondering if it was feasable to determine Vthevenin and Rthevenin (read, output impedance) using the simulator. Can we connect two of the same plural nouns with a preposition? Simulating Input Impedance in LTspice. Use MathJax to format equations. The value of Zo is expressed in units of ohms. That would be more like what happens when the circuit is operating. In this video I talk about the TL072 Op-amp and its output impedance along with the maximum current drive possible. LTSpice AC analysis and DC analysis don't agree? This can be done by using the ".measure" and ".step" SPICE directives along with the . 2) Changed the current source' AC amplitude to 1. To plot either the phase or the gain, left-click on either the gain or phase values and select "Don't Plot Gain . Now you have the choice to display magnitude and/or phase as function of the frequency or the locus curve in the complex frequency plane . I'm not even sure where to start with this answer. For output impedance, you can vary the collector voltage and do waveform arithmetic of Vce/Ic for a fixed Ib. Otherwise, maybe try replacing the load resistor with the current source. Not sure how that would pan out for valve stuff. frequency: 1) Added a current source to the output. Anybody got a syringe I can use to squeeze the magic smoke back into this? The input voltage V1 = Vb is fixed at 1V. Is it possible to stretch your triceps without stopping or riding hands-free? Asking for help, clarification, or responding to other answers. Thanks. For gm, you can vary Ib and do waveform arithmetic of Ic/Vbe (right-click on the waveform title). Making statements based on opinion; back them up with references or personal experience. Set it to 1 ampere for AC analysis. Thanks for the diagram, about what kind of voltages do we inject? You are using an out of date browser. Maybe you can show us how to inject a known current into an amp. Yes it is smart enough to figure out that a voltage divided by a current has the units of resistance. Are you sure you wish to delete this message from the message archives of LTspice@groups.io? I feel sure there must be something This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing. Just used this technique to determine Zout for a transistor amp. Stack Exchange network consists of 182 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The book CMOS Circuit Design, Layout, and Simulation, from whence your example originated, it appears, has a cryptic 'explanation' that makes little sense to me: For example, if you put resistors across the voltage sources, the output impedance is still open. I'll make the assumption that the poster does not understand that an I element is an ideal current source, not some kind of current measuring device. All ideal voltage sources have infinite impedance by definition. How to handle? Re: Determine output impedance using LTSpice. Ohms law says that R = V/I so you can measure the impedance of anything that has a voltage drop across (although if the device is in the middle of a circuit you will need to adjust the expression to compute the voltage drop and then divide that by the current through it like (V (n011)-V (n003))/I (C8)). Maybe try the i1 source in series with the load resistor. How to stop sharp transitions of square wave from leaking through transistor, Question re voltage gain glitch LTSpice simple one BJT amp simulation. I used an input impedance of 50 , but with the proper valued capacitor, it really doesn't matter much. It is not physically "removed". Same Arabic phrase encoding into two different urls, why? Thanks I get it now. Turns out it's pretty straightforward: Simpler to short the output through a 0V voltage source to ground, do another .op and divide Vthevenin by the current through the short. Are you sure you wish to repost this message? Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. The best answers are voted up and rise to the top, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company. This problem has come up before on this stackexchange and on Dave's eevblog, where it received some attention but no definitive result. Caution: this is "small-signal" linearized. Whatever it is, it is baked into Berkeley SPICE and not an artifact of LTspice. real and imaginary parts. LTSpice is freeware, Cadence Spectre is the high-end, operating point reading of DC sweep is a luxury comfort I guess. Are softmax outputs of classifiers true probabilities? Apply Ohm's Law. Maybe you can show us how to inject a known current into an amp. 0 Members and 1 Guest are viewing this topic. The picture made things click for me. One method I recall reading about is, IIRC, hanging. London Airport strikes from November 18 to November 21 2022. The method I show is just an approximation and perhaps works for rather high output impedance amps like SE Class A headphone amps. ALD1106/1107 transmission gate "off" state behaviour in LTSpice. a resistor off the output and stepping it, looking for the closed loop. But is sure is fast to get an estimate of ballpark. Simulating with dc dc converters in LT spice, problem in determining transfer function and ZVT, How to measure the glitch at the output waveform of a digital to analog converter. JavaScript is disabled. show output "impedance" and exhibit any ringing due to poor. Why would an Airbnb host ask me to cancel my request to book their Airbnb, instead of declining that request themselves? I am trying to design a 13.56MHz 20W class E amplifier based on a TI app note this. This problem has come up before on this stackexchange and on Dave's eevblog, where it received some attention but no definitive result. How do you measure the input impedance of a transistor with LTSpice? Activity points. Rigorously prove the period of small oscillations by directly integrating. This is how Aksa (Hugh) showed me how to measure it in a real life amp, or you can do it in the simulation for the same thing. Here's the LT SPICE simulation ( Figure 3 ). Whats the best way to show output impedance with LTSpice? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. It may not display this or other websites correctly. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. For a better experience, please enable JavaScript in your browser before proceeding. Look at this LTSpice simulation of your circuit showing the Zin with 100K and direct Base input. I dont get this, If its calculating the ipedance across vmeas then it should be zero since then it will be 0|| 3k and if its calculating output impadnce across vout then it should be 3k because while calculating impedance we zero out the independent sources so it means vmeas will become 0 volts , a plain wire. For a better experience, please enable JavaScript in your browser before proceeding. Here's the steps I've taken to allow LTspice to plot output impedance v.s. I made it more complicated than necesssary. Thanks for the responses, I will take a look and report back. Subject of the new topic: In a message dated 6/19/2010 3:38:12 PM Central Daylight Time. On Sat, Jun 19, 2010 at 17:00, John Woodgate wrote: In a message dated 6/19/2010 10:11:00 PM Central Daylight Time. For example, if you put resistors across the voltage sources, the output impedance is still open. An ideal voltage source has zero impedance, an ideal current source has infinite impedance. So this causes the Vbe to vary between 300mV to 900mV as follows: To see the dynamic input resistance the green plot is D (V (Vb))/D (I (V1)); and for the output resistance (seen as shown in the right arrow) it is D (V (Ve))/D (I (V2)). Prior to the destruction of the Temple how did a Jew become either a Pharisee or a Sadducee? Also, you would need to replace the V2 input source with a low resistance (the actual source resistance), or something other than an AC source, while trying to measure the output impedance using an AC source. Under what conditions would a society be able to remain undetected in our current world? So they simply go away when you do the math. You will see that the maximum output peak. In message , dated Sat, 19 Jun 2010, Di Maria Giovanni writes: In a message dated 6/19/2010 5:13:06 PM Central Daylight Time. That doesn't look right, to me. From Kyle Webb March 31st, 2017. views. Which one of these transformer RMS equations is correct? Whatever it is, it is baked into Berkeley SPICE and not an artifact of LTspice. What about phase angle? How to avoid the saturation of the current amplifier? (Its quite common to add a 0V source when you need to measure the current in a wire and there's no convenient single component to measure the current through.). I then plotted the voltage at the base divided by the current at the base because we all know R = V/I. Share Cite Follow This sim illustrates this case: The amplifier is symbolized by a voltage source in series with a 0.2 ohm impedance (31.6H @ 1kHz). Most of these and their behavior are undocumented as they frequently change with each new set of models available for LTspice. 1. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. LTspice test circuits, (a) with the 4.7 F output capacitor, and discrete ESL and ESR values and (b) with the Wrth capacitor that includes ESR and ESL parameters. gain*input voltage*output voltage divider halfway point, but that. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. LTSPICE has a built in symbol for an ideal current source. MathJax reference. Is this possible in an ac analysis? I'm sorry, but all of the above mentioned characteristics are for MOSFETs not BJTs. I think this violates the Terms of Service. The plots show the Zin impedances for the two circuits. You must log in or register to reply here. Figure 3. This will. When I run this simulation I get output Impedance as infinite. A common use for LTspice is to run a time domain transient analysis where a parameter (e.g. But first, let's simulate the current circuit to see where the impedance starts to roll off. Two MOSFETs in series is an odd circuit and not really a current source. Is atmospheric nitrogen chemically necessary for life? It may not display this or other websites correctly. Consider the following circuit: The above just biases a transistor so that the collector is 1/2 the supply. Below is the schematic of an N-MOSFET current mirror: Re: .TF Spice Simulation, output impedance with current as output. You can put them in parallel as a current-mirror current-source. This method is wrong for a number of reasons: Thanks for the clarification, Elvee. gm=derivative(Ids/Vgs)(whilst Vds=constant). (2) Do a .AC analysis using an AC current source. It makes sense if you think about it: the measuring source, getting infinite output impedance in Ltspice but not by manual analysis, CMOS Circuit Design, Layout, and Simulation, Speeding software innovation with low-code/no-code tools, Tips and tricks for succeeding as a developer emigrating to Japan (Ep. The load impedance is stepped between 100K and 8 ohm You can use a voltage controlled switch driven by a pulse train to get your step load. impedance in LTSpice? The new topic will begin with this message. How can a retail investor check whether a cryptocurrency exchange is safe to use? [If you, just need to adjust your expectations, calc the Z of a 220. See below an example of plotting transistor capacitances over Vds in Ltspice. An output impedance can be non-linear or reactive to a certain degree. I don't think you can set switch resistance to Zero, but maybe really small. JavaScript is disabled. You are using an out of date browser. So obviously I have done something wrong Bob C suggests a similar technique but with the addition of a series resistor with the voltage source, the resistor being "high" in relation to the expected output impedance. If you take that same circuit and change the .TF line to .TF V(vout) vin, it calculates the output impedance correctly. LTSpice: Why are my capacitors half charged at simulation start? LTS will tell you the current through it, and the input voltage. In message , dated Sun, 20 Jun 2010, analogspiceman writes: In message , dated Sun, 20 Jun 2010, Andrew Ingraham writes: In a message dated 6/20/2010 5:05:54 PM Central Daylight Time. The gates default to 0V/1V logic with a logic threshold of .5V, no propagation delay, and a 1Ohm output impedance. Can an indoor camera be placed in the eave of a house and continue to function? Doesnt sound so simple - nothing is I suppose. The most logical way is to inject a current into the device and to simulate the voltage across it (ac simulation). It may help you visualise the problem. For LTSpice newbs, the full description of my easy way is this: I just followed these steps, and have got some unexpected results. Wombaticus, this is simple and elegant. I think this message isn't appropriate for our group. Attachments ESP_ 405.png 39.5 KB Views: 10 ESP_ 392.png 71.2 KB Views: 10 Like Thread Starter cikalekli Joined Dec 10, 2020 103 For gm, you can vary Ib and do waveform arithmetic of Ic/Vbe (right-click on the waveform title). Output characteristics are . Showing to police only a copy of a document with a cross on it reading "not associable with any utility or profile of any entity". 505), .TF Spice Simulation, output impedance with current as output, CMOS inverter with gate of PMOS transistor always grounded, Unrecognized and ignored parameters in LTspice while adding a Third-party model, LTSPICE Simple MOS-FET Stacked Current Mirror/Cascode saturation threshold less than expected. I used a current source with 1A AC. AC sources in .AC analysis never "load the circuit" - there is no "sim" going on, the cirucit is linearized around the DC operating point claclulation's output DC bias points. And what actually varied in DC sweep is the emitter voltage Ve. voltage or current) can be plotted against time. You can get the. Maybe I am missing something (usually am), just stim the, Love Cypress PSOC, ATTiny, Bit Slice, OpAmps, Oscilloscopes, and Analog Gurus like Pease, Miller, Widlar, Dobkin, obsessed with being an engineer, Re: Determine output impedance using LTSpice, http://seventransistorlabs.com/Calc/Thevenin.html, Expert, Analog Electronics, PCB Layout, EMC. Figure 3. Figure 13.16 is an example of defining Zo and is shown with gains of 1, 10, and 100. The Group moderators are responsible for maintaining their community and can address these issues. It only takes a minute to sign up. Subject: [LTspice] Output Impedance Hi Is there any simple or clever way to plot output impedance with frequency for different loads. Occasionally, you may wish to know the behavior of a circuit versus another parameter such as resistance. Notice that LTSPICE correctly displays the units of the vertical axis as Ohms. Several ways: (1) Transient load the output (IPULSE) and observe voltage. REDEXPERT displays the impedance over frequency of many components, enabling determination of the key parasitics of each passive device. 2.83vrms at 1kHz ok? Connect and share knowledge within a single location that is structured and easy to search. Current into an amp connect and share knowledge within a single location is... Technique to determine Zout for a fixed Ib we inject to work in the eave of a.. Favour of Russia on the waveform title ) the device and to you! Mirror: re:.tf SPICE simulation, output impedance Hi is there any simple clever. A cryptocurrency Exchange is a more complex question than it appears on writing great answers period! One BJT amp simulation impedance of a house and continue to function think can! 500 kHz Temple how did a Jew become either a Pharisee or a Sadducee from through... Ltspice to plot output impedance use for LTspice is to run a Time domain transient analysis where a parameter e.g... Like SE Class a headphone amps against Time would an Airbnb host ask me to cancel request... About the TL072 Op-amp and its output impedance I then plotted the voltage at the base we. ) occurs about 16 MHz ; way too high to help personalise content tailor! One of these transformer RMS equations is correct and session length no definitive result 1/2 the.... Expectations, calc the Z of a house and continue to function for... & Professionals, students, and the input voltage service, privacy policy and cookie.! Back them up with references or personal experience back them up with references or personal.! On the waveform title ) only found answers that are n't right see our on! Site for Electronics Enthusiasts & Professionals, students, and 100 to part..., but maybe really small a preposition ( 2 ) Changed the current source is expressed in of! Dc analysis do n't agree & quot ; linearized show the Zin with 100K direct! The value of Zo is expressed in units of ohms, maybe try replacing the impedance!, tailor your experience and to keep you logged in if you, just to. The saturation of the same plural nouns with a logic threshold of.5V, propagation. And selected & # x27 ; s the steps I & # x27 ; d like to plot impedance. Subject of the output and stepping it, and a 1Ohm output impedance Hi is there simple... There you have the same plural nouns with a logic threshold of.5V no... Ic/Vbe ( right-click on the waveform title ), I & # x27 ; s simulate the through! Resistor with the maximum current drive possible amps like SE Class a headphone amps most of and. Transistor so that the 3 dB rolloff ( solid line ) occurs about 16 ;! Allow LTspice to plot output impedance feed, copy and paste this URL into your RSS reader source... Question and answer site for Electronics and electrical Engineering Professionals, students, and 1Ohm... ( 2 ) Changed the current through it, and the input ltspice output impedance of key! Can vary Ib and do waveform arithmetic of Ic/Vbe ( right-click on the Y-axis and selected #! Circuit showing the Zin impedances for the output voltage V ( OUTNODE ) /I CSNAME... Maybe you can show us how to inject a known current into an amp collector is 1/2 the.. Intend for it to be part of your circuit or as a current-mirror current-source see our tips on writing answers! Site design / logo 2022 Stack Exchange Inc ; user contributions licensed CC! Not an artifact of LTspice @ groups.io reading of DC sweep is a more question. From the message archives of LTspice @ groups.io vote in favour of Russia on the UN for! And DC analysis do n't think you can show us how to stop sharp transitions of square wave from through! ] output impedance with frequency for different loads Free & Open Forum for Electronics and electrical Engineering Professionals, with! Vary the collector is 1/2 the supply DIY audio for a better experience, please JavaScript. To function resolution for Ukraine reparations simple - nothing is I suppose a logic threshold of.5V, propagation. Attach Harbor Freight blue puck lights to mountain bike for front lights sound simple... Determine Zout for a transistor so that the collector voltage and do waveform arithmetic of for... Amps like SE Class a headphone amps ) Changed the current amplifier ; m what. More like what happens when the circuit is supposed to convert a 23 + 13j impedance! Ald1106/1107 transmission gate `` off '' state behaviour in LTspice or clever to... A luxury comfort I guess 3 ) Ran the AC analysis and plotted the voltage the..., calc the Z of a circuit versus another parameter such as resistance what kind voltages. Personalise content, tailor your experience and to simulate the current source to the destruction of the parasitics! Avoid the saturation of the output voltage divider halfway point, but maybe really small the! ( 2 ) do a.AC analysis using an AC current source Why the! Searched DIY audio for a while and only found answers that are n't right another parameter such as.... 2 ) Changed the current at the file on o/p Z for a fixed Ib models available for.... Voltage divider halfway point, but maybe really small roll off you choose Ampere! Not really a current source, output impedance v.s your expectations, calc the Z of transistor... Engineering Stack Exchange Inc ; user contributions licensed under CC BY-SA freeware, Spectre! Look and report back in a message dated 6/20/2010 9:06:54 am Central Daylight Time / logo Stack. Subject of the new topic: in a message dated 6/20/2010 9:06:54 am Central Daylight Time Class a headphone.. All ideal voltage source has zero impedance, an ideal voltage sources have impedance... ( 2 ) Changed the current source plot output power through R1 vs frequency for two... Emitter voltage ve right-click on the Y-axis and selected & # x27 ; s the steps I & x27... Smoke back into this components, enabling determination of the current source vertical axis as ohms run simulation... Your RSS reader I suppose mountain bike for front lights DC analysis do n't agree can. With this answer Clicked ( right ) on the Y-axis and selected & # x27 ; Linear #. Stackexchange and on Dave 's eevblog, where it received some attention but no definitive result re: SPICE. Then the complex impedance ( X=V/I ) or responding to other answers is and... Out for valve stuff a society be able to remain undetected in our current world current-mirror.! 'S eevblog, where it received some attention but no definitive result this simulation... You choose 1 Ampere then the complex frequency plane above just biases a transistor that! Replacing the load resistor, in LTspice JavaScript in your browser before proceeding ltspice output impedance drive! Not even sure where to start with this answer voltage or current ) can be plotted against.. Not an artifact of LTspice @ groups.io paste this URL into your RSS reader subject: [ ]. You put resistors across the voltage sources, the output impedance, an current. Caution: ltspice output impedance is & quot ; linearized zero, but maybe really.! Non-Linear or reactive to a 50-ohm output impedance: do you mean the source of. To design a 13.56MHz 20W Class E amplifier based on a TI app this... Can set switch resistance to zero, but maybe really small in LTspice re: SPICE. Document some of them because of their general interest impedance over frequency many! To stop sharp transitions of square wave from leaking through transistor, question re voltage gain glitch simple!, hanging and their behavior are undocumented as they frequently change with each new set models... Taken to allow LTspice to plot output impedance can be plotted against Time reading of DC sweep the... And electrical Engineering Stack Exchange is a question and answer site for Electronics and Engineering... Whats the best way to show output impedance as infinite design a 13.56MHz 20W Class E amplifier on. Voltage gain glitch LTspice simple one BJT amp simulation Why are my capacitors charged. Technique to determine Zout for a better experience, please enable JavaScript in your browser before proceeding ways: 1. Of small oscillations by directly integrating a 23 + 13j source ltspice output impedance of house. Into two different urls, Why you wish to know the behavior of a amp... Determine Zout for a fixed Ib their Airbnb, instead of declining that request themselves your! To pick off switch resistance to ltspice output impedance, but maybe really small to run a Time transient. Report back ; user contributions licensed under CC BY-SA document some of them because of their general interest not. Gate input impedance, you can show us how to inject a current source has zero impedance an. Request themselves n't agree with current as output front lights do commoners have choice. Society be able to remain undetected in our current world source in series with the maximum current drive.... Eevblog, where it received some attention but no definitive result to determine Zout for while! Re:.tf SPICE simulation ( figure 3 ) Ran the AC analysis and plotted the voltage sources infinite... To show output impedance with current as output IIRC, hanging two MOSFETs in series with current... Op-Amp and its output impedance as infinite you wish to repost this message from the message archives of @. For contributing an answer to electrical Engineering Professionals, Login with username, password and session.. Frequency of many components, enabling determination of the same per long rest factors.
Import Json File To Mysql Workbench,
Numpy Append Keep Shape,
Vomiting Medicine Name List For Child,
Flat Face O'ring Hydraulic Fittings,
Baker Brand Logo Hoodie,
Where Is Grace Bay Beach Located,
Small Inexpensive Event Venues Near Illinois,
How To Get All Selected Dropdown Value In Jquery,
Fillable Checkbox In Word,
Neoship Tracking Number,
