LTspice tutorial - EP3 .param and .step directives

[@Graham_Wideman]

Came for the .param and .step, got bonus tip on dragging a wire across multi components to hook them all up at once. Now that's a time-saver!

[@mrsc1914]

awesome pace. It was like hearing a human speak rather than a pigeon. thnx

[@FesZElectronics]

@Mr Sc1 . I'm happy you are enjoying my content! Ah yes, pacing; at the beginning I tried to make things really fast paced because I hated all the other tutorials that just took for ever to say something that can be said in a quarter of the time. But I think I somehow got into the other extreme, I mean, during editing I cut out every sort of pause to the point the speech doesn't sound natural any more. Honestly I'm not sure what the "right" pace is, must be different for everybody, but I try to keep things fast but also easy to follow and understandable.

[@mrsc1914]

@@FesZElectronics Ya, its funny world right. Your good

[@tavorebisu]

Now I know I can draw wires through the components. Nice

[@mynameiswesker]

My teacher introduced this software for us at class even though it was not at the school schedule. So we could study at home if we want. Im studing with you now. And it s pretty cool. A lot of stuff can be done.

[@FesZElectronics]

I'm happy you are enjoying my videos! The main reason why I personally like LTspice is that its a proper simulator - its a serious professional simulation software and even though its not that easy to use, since its free, there are so many tutorial out there you can find an answer to any problem.

[@zauletandrei]

Short and helpful. Thank you, sir!

[@HongPan-n9r]

is it possible to plot the result against sweep value?

[@paulobelarmino6455]

Bom dia. Onde obtenho tutoriais iguais a este em PDF? Grato.

[@lovutube1231]

Great video, great info, and great service to the EE community BUT no excitement in your voice or the narration of the topic, Thanks anyway for teaching me. And I did subscribe.

[@jeffreyhu3775]

I want ask one question, how to jump different curve in diagram when I active in cursor function? I see you in video timeline 5:52. thanks.

[@FesZElectronics]

Once you select the plotted trace of interest, you have the arrow keys, by pressing up and down you can cycle between multiple plots that where generated using .step statements.

[@qzorn4440]

i am finding out that ltspice can help with creative circuit designs.. then breadboard to comfirm the beast... thanks and great info..:)

[@FesZElectronics]

It's much easier to try a bunch of different values for components in a simulator than in real life. Cheers!

[@NMECSHAMANTHKS]

You are a god. Thank you so much. You made my day today.

[@SohamChakraborty42069]

The speed at which this guy made the first circuit, even Flash got ashamed.

[@ChristianRThomas]

Nothing about curly brackets and when to use them, or the problems with doing simple arithmetic between two variables in a .param statement?

[@sahabtareq]

man i have the same problem. i am getting 440 solutions , i need 40 only. but its stepping all the possible numbers. looked around the internet with no way to step it properly. let me know if you find something

[@sahabtareq]

hey there once again, so i kept trying stuff around. in my case i had 2 changing resistors (one increases by x )(other decreases by x ). what i have done is set {w} as a parameter for both resistors. like this R1={w} R2= - {w} i hope you are doing the same thing. good luck

[@victorlee8451]

Very helpful thank you!

[@FesZElectronics]

I am happy you liked it!

[@abdelazeemhassan3701]

Great discussion very good, amazing

[@najeebqureshi4821]

can you make video to show how to generate a signal with variable amplitude?

[@radiga925]

How do i make the simulation for only the correspoding values in the 2 lists and not for all possible combinations?

[@FesZElectronics]

I guess the best way would be to make the second value an expression related to the first; say you want to simulate in case 1 a 1K resistor and a 5k resistor; and in case 2 a 2k and 10K; you could express value 2 as {value1*5}

[@Eisraman]

You are better than great!

[@fabriziolavini7457]

Great explanation, many many thanks for your effort. Though I noticed anomalies on values calculated, so on the simulation itself. Made the simpliest system with a dc supply voltage 10 V (no internal resistance), a resistor (set the resistance only) and a capacitor 1.000 uF (set the capacitance only). So i changed the resistance only, from 0,001 ohm to 100 ohm (manually, step of decades). Made a transient simulation : .tran 1 (or 10 or 20 depending on resistance) Time constant is calculated differently depending on resistance. R = 0.001 -> RC = 1 us => 61.24% R = 0.01 -> RC = 10 us => 61.18% R = 100 -> RC = 100 ms => 63.22% Calculating 10 x (1 - EXP(-1) ) would give 63.21 %. Differences even with peak currents. Is it explainable ? If you prefer a better way to send you data please let me know. Thank you again

[@FesZElectronics]

When a transient simulation gets performed, the program will not calculate every possible timestep; there will be a certain blanking time in-between steps, where the output plot is just an interpolated line; This will also be visible when performing an FFT on a sinewave - unless you take some precautions, the wave will be highly distorted; The main reason for this is to keep simulation time reduced while still providing useful even if approximate information, so its not really a bug but a feature. I think this is the issue in your case as well; You can try to force the simulator to have a fixed maximum timestep - something small - its in the transient window editor - the 3rd entry. May I ask how you calculated the time constant using the simulator?

[@fabriziolavini7457]

​​@@FesZElectronics thanks again, in this case for the useful advice. First of all your question. Actually I said it improperly. I calculated the time constant with the usual formula tau = RC so in my case always 1 us. What I noticed is that if I used the definition of time constant as the time to reach 63,21205... % of supply voltage, I would have calculated different time constants (i.e. > 1 us), simply misuring differences about these percentages. About your advice. I summarize the conditions. Vs = 10V | R = 0.001 | C = 1000u This what you can't get at 1 us for voltage across the cap and peak current throught cap. 1) .tran 1 -> 6.12391 V | 9.9800 kA 2) .tran 0 1 0 1p -> after 3 min still 0% done 3) .tran 0 10u 0 1p -> 6.321205 | 10 kA | about 1 min to complete 4) .tran 0 10u 0 1n -> 6.3213843 | 10 kA | immediate 5) .tran 10u -> 6.3223453 | 9.999998 kA So, as you guessed using parameter max timestep: (3) is the most accurate but a little slow (acceptable) Useful was of course setting the total time more properly to complete the simulation in a smaller time (1 s -> 10 us) THANK YOU again

[@abirtayouga3195]

my native language is not english so you explain fast , but i understand a little bit thanks

[@benevolentowl]

Mil vezes obrigado. Já estava sem esperanças.

[@cassiuspeter9673]

Is there a way to use the step directory when modelling a circuit where average power dissipation is key? I tried using the step directory, and while it provided the multiple simulations I needed, there was no way I could find to calculate the average power dissipation.

[@FesZElectronics]

Hello Peter. That can be done using .meas statements; simply place one anywhere in the circuit and it will output the measured value in the error log (View->spice error log) The measurement is done on each simulation run. For example if you want to measure the power dissipation on resistor R1 which is connected to nets n001 and n002 the meas statement will look like: .meas Paverage AVG V(N001,N002)*I(R1)

[@scisyhp_]

How to add required spice model in simulation

[@FesZElectronics]

Hello! I covered this in a later episode: kzbin.info/www/bejne/boeYiZSYmMh5l6c

[@fromnaturetonature6424]

.inc ,.IC indicates for???

[@FesZElectronics]

.inc stands for "include" - this is used to include library files; .ic stands for "initial conditions" - this is used to set voltages and currents in the circuit at start of simulation

[@juanjorojash]

Great! How do you copy the parameters from one component to the other so fast?

[@FesZElectronics]

Hello! Well on the first component I did Ctrl+A (select all) then Ctrl+C (copy) and then on the next components Ctrl+v (paste) and of course, the fast forward editing helped.

[@maximinblanc4240]

Thanks a lot for this quick reminder. I wonder if we can have a step simulation with 2 parameters linked by table. Let me explain an example : 3 values of R related to 3 values of C which gives the same cross frequency We would like to compare R1C1, R2C2 and R3C3 only (not the 6 other couple) is there any tips to do this ? like .step (R C) list ((R1 C1) (R2 C2) (R3 C3))

[@steved1122]

Very good !! thank you !continus ;-)

[@singlehanded12]

Brilliant, thanks for your effort.

[@Graham_Wideman]

Folks watching this video may also be interested in the 'table' function.

[@FesZElectronics]

I did not explicitly cover the table function, but I made use of it to step sets of paramters - so multiple parameters at the same time - kzbin.info/www/bejne/Z5qyq4tvZrF9bsk

[@camilotello3296]

I love it!

[@raghuveera3519]

great job sir , is there any source to read about ltspice stimulation..

[@FesZElectronics]

Hello there! Since this simulator is so widely used, there probably is, just depends on what exactly do you want - there is a lot of documentation available from Analog Devices (they own LTspice) and from third parties also. Is there any particular subject you wish to learn about?

[@wefeelitweliveitnaugthy]

salam tu peux me montrer comment former un hacheur ? et merci

[@howieg]

Why did he speed up his video by 25% before uploading it? Hit the setting button in the lower right corner to reduce the speed.

[@FesZElectronics]

I didn't speed things up, I just cut out all the pauses I took between words. Its a thing I tried to correct in later videos to make things more natural.

[@fnc.service]

gracias loco, sos crack

[@mehmetgur4478]

thank you!

[@FesZElectronics]

Thank you for watching!

[@alexgeh4875]

Some actions are done too fast for a tutorial presentation to follow. Otherwise a well-thought tutorial.

[@semiconductorschematicdesign]

This is good, but you could have made it a bit slower so that I could understand properly your steps. So not much helpful for now

[@lupoal4113]

Sorry but I do not understand ... with these videos you want to help those who watch you or you just want to prove that you are a phenomenon? because judging by the speed with which you load the parameters you ... you are a phenomenon! but who cares! it is so fast that we do not learn anything :(