LTspice Tutorial - Voltage limited current source and Current limited Voltage source

[@hannuhanhi183]

Great stuff mister. Best LTSpice tutorials on the KZbin. Keep up the good work.

[@FesZElectronics]

Thanks, will do!

[@robinhood7259]

you answer my questions which typically came up when I use LTspice very often. Great Videos about models inserting, simulating, comparing with data sheet, knowledge about electronics in general, etc. Thank you very much.

[@FesZElectronics]

I'm happy you are enjoying my videos! Let me know if there would be any subject in particular you would like to see in the future.

[@robinhood7259]

@@FesZElectronics Here are some ideas. When I searched for simulating an inrush limiter I found this page: poulpetersen.dk/notes/ntc.html It's about variable resistors in general. But I don't understand all. Maybe you could make a video about variable resistors? One similar topic (but I don't know if this is common) is how to simulate the variability of inductors due to core saturation effects. But maybe this is not necessary if the inductor is calculated properly with a good safety margin to saturaton.

[@FesZElectronics]

Regarding inductor modeling, I did cover the topic a while back - kzbin.info/www/bejne/bGbJf3eIpNymb5I ; there is also a similar video on capacitors. Regarding thermistors, I wrote it down and will try to cover the subject in the future. Thanks for the sugestion!

[@FesZElectronics]

Regarding inrush limiting - what you need is a PTC thermistor (Positive temperature coefficient - with increasing temperature resistance increases), looking quickly on the link you shared, they where talking about NTC's (Negative temperature coefficient - with increasing temperature resistance decreases). I found this page by Vishay and they link a full LTspice library with PTC's - maybe this helps www.vishay.com/whatsnew/doc/ff_FastFacts_LT_SPICE_PTCEL_CL_TL2.pdf

[@robinhood7259]

​@@FesZElectronics very nice! exactly what i was looking for.

[@AndrewKiethBoggs]

Just joined patreon for support, your content is great!

[@jackhuffman1582]

Your current limited voltage source simulator is brilliant! Its not intuitive to me. Just what I was looking for. I really like your videos.

[@FesZElectronics]

Thank you! Great to hear that!

[@RaviKumar-xx7gi]

Hi I have made the circuit of LM317 on bread board. I am generating a constant current of 100mA. The input to the regulator is 3.3vdc. 100mA constant current is fed to a resistor of 100 ohms. I should measure a voltage across resistor of =10mA x 100= 1000mV=> 1V, but the voltage across the resistor I am measuring is 3.3vdc. why so? I want to use the constant current source to find the unknown resistor using current and voltage How can I do this?

[@FesZElectronics]

For the LM317 the minimum input voltage is 4.25V; I think that since you are using a 3.3V supply the IC is not working correctly.. However, if the output is exactly the same voltage as the input, there might be a mistake in the circuit - usually the output of the LM317 should be 3V or more smaller than the input.

[@samuelverdeflor7768]

Great free software! Kudos to developer and tutors!

[@FesZElectronics]

Glad you think so!

[@RickThePeasant]

Would this be a good model for a solar panel?

[@DerelictEarth]

Thank you it will be very helpful in my current issues ...

[@jurajmarek9175]

Hi, Thank you for good idea. However, I tried to use your voltage limited current source to simulate gate charge of MOSFET (2N7002) and it cause lot of troubles, so I little bit modify it. First of all I add 1g resistor in parallel to diode and voltage source and next specified ideal diode just by Dideal D (Vj=1m). Then it works.

[@jurajmarek9175]

Ohh, now I realize, that my diode is not so ideal. There will be 0.4 still voltage drop. Because LTSpice will reject small values of Vj and Eg ... But for my case, gate charge simulation, it works at least ...

[@tux1968]

Hi there, really love all your videos! Why not create a new model that hides your extra circuitry and just lets you use a current limited voltage source as a component with its own unique symbol?

[@FesZElectronics]

That of course is possible. I just left the circuit with basic parts to clearly show how it works.

[@tux1968]

@@FesZElectronics Okay, fair enough. Am just watching another one of your videos now. You really know your stuff and it's great how well you explain things. Much appreciated.

[@FesZElectronics]

Thank you for the kind words! I'm happy you are enjoying my content!

[@Huzaliproductions]

Thank you :)

[@sudeepbanerjee6934]

as i can see you have a great knowledge of LT spice,please help me out . I am facing problem to get Operational trance conductance amlipfier(OTA) all result(ac,dc analysis,gain etc) i m very greatfull if you help me out. send your mail so that i can provide you specifications. reply soon thankyou