LTspice tutorial - Modeling Switches

[@electronics.unmessed]

Well done! I like the mechanical switch analysis on the oscilloscope!

[@olivierconet7995]

Oh nice, I didn't remember that it was possible to speed up a relay when opening. Thanks for the refresh !

[@airmann90]

Hey man, love your videos! The last transistor ones had me at my breadboard testing all the different biasing methods. Lots of fun to play around with while heating and cooling the transistor, etc. Really solidified how much more testing and tinkering I should be doing with my circuits.

[@pfabri]

Very useful topic, thanks!

[@gkdresden]

The on and of bouncing is very characteristic for a relais. On bouncing typically starts with longer open intervals becoming progressively shorter with time. A good relais has no bouncing at all. I use to implement a .pwl file to describe the on bouncing. Therefore I measured the characteristic behaviour of the relais. Then I used a script tool to implement the relais behaviour into the control .pwl file.

[@dr.imayavarambanmunuswamy808]

Many thanks for your time Sir. Great Well Explained.

[@ge6ge]

is there a bug at 6:18? In Model5 I have to use Vser=-1V to get the same results as in your simulation. With Vser=+1V I get at V(n003) +10V and -1V

[@biswajit681]

Excellent... expecting videos more frequently 😃

[@FesZElectronics]

I'm happy you enjoyed it! For the moment I will stick to 1video/week for 2 weeks then 1 week break - its the best I can do.

[@bobby9568]

really well explained!

[@ibanix2]

Good video! I was wondering how you were going to model switch bounce and your solution is nice. I used voltage-controlled switches in the past as poor approximations of spark gaps. The challenge there was to get the switch to turn on slowly but turn off rapidly when a lower threshold voltage was reached. I never quite found a good solution. Also I didn't know that relay trick with the zener diode. Nice.

[@FesZElectronics]

For a spark gap, I think I would go for a gas discharge tube model - there is one in LTspice; this nicely replicates the high turn on voltage, then the lower maintaining voltage. The model is under "misc" called "neon bulb".

[@metal9lover9maniac]

Why can't there just be a pushbutton component and model?

[@philippepaternotte2965]

@FesZElectronics Hi, very interesting subject. On relays: You may explore the double-coil tweaking methods (one coil as "normal", one shorted by a diode, a diode with a resistor, etc.). In ol' times electromechanical phone exchanges had a lot of relay tweaks; also copper rings to slow down responses...

[@FesZElectronics]

I haven't looked into the intricacies of relays all that much, but I think there is a lot more to explore! Thanks for this feedback!

[@pieters286]

The impact of higher flyback voltage in switching element breakdown voltage need to be checked.

[@FesZElectronics]

In the particular experiment in the video, I specifically used a 30V zenner since the transistor I used, BC847, had a breakdown of 45V.

[@almenbrenoli2942]

Hey, I have one question. I have a project where I need to model Motion sensor by using NE555 Timer, where I use aluminium foil, and that aluminium foil checks any movement by hand or something else. I need to test this circuit in LTSpice, any suggestions what can I put in LTSpice instead of aluminium foil(because it doesn’t exist in LTSpice 😂)

[@FesZElectronics]

To be able to simulate it, you first need to know what is the electrical parameter that changes with the aluminum foil. If its capacitance, then it can be modeled quite easily.

[@almenbrenoli2942]

@@FesZElectronics Can I contact you via email ? 🤗