Personally I have seen a lot of cases where someone just cobbles up a circuit in a simulator, puts in some random values and says great it works, but he doesn´t have enough experience to see that he is using an ideal opamp that exceeds its power supplies and a whole lot of ratings of components like mosfets etc. is way exceeded, and the circuit will blow up when first turned on.

Okay, treat the experience as learning, go back to the simulator, read the datasheets and do better next time.

 

I would just like to ask :- Without a firm understanding of at least basic fundamentals, how can you decide what to simulate?

 

I would just like to ask :- Without a firm understanding of at least basic fundamentals, how can you decide what to simulate?

I don't know the answer but, hang around the site for a while, you will see the attempts.

 

Without a firm understanding of at least basic fundamentals, how can you decide what to simulate?

If a person has poor vision, how can he drive safely?

I think you are arguing against an situation for which no reasonable person is advocating.

 

Without a firm understanding of at least basic fundamentals, how can you decide what to simulate?

Well, you can decide to simulate someone else's circuit design; but of course you won't have a clue what the simulation results tell you .

 

..."those who have no clue what they´re doing" will be incapable of using a simulator, they are difficult to use and you do need more than a clue to get them to work. However for people learning electronics, simulators can be a useful "playground" in which to learn in parallel with making and testing circuits. In the professional world simulation is essential, I've worked on projects that simulate the electronics, the electro-magnetics, the system mechanics and the digital control.

Sadly, in my experience people on the "no clue" end find simulators far easier to work with than a breadboarded circuit and actual bench testing. Mind you, they don't know how to do either correctly, but it is easier for them to convince themselves that they know how to do a simulation.

I fully agree that the most effective learning is going to be one that includes both simulation and actual circuit construction in parallel. Unfortunately, the trend in engineering education is strongly away from actual circuit construction because simulation costs a lot less.

The first time I taught the Electronics II course I had only two weeks notice and so I didn't have much choice but to just follow the prior prof's syllabus. In it were three projects in which students had to design a circuit, simulate it, and write a report. Overall, this was a class consisting of some very bright students -- very possibly the brightest class of any that I have ever taught -- yet the circuits and reports they turned in were garbage. They simply did not understand what the simulation results were and were not telling them. So the next year I came up with a similar set of projects but this time the students had to design a circuit, simulate it, build it, test it, demonstrate it, and then write a report. Overall, this was a class consisting of some of the weakest students I had ever seen and the first project was an absolute blood-letting. But by the end of the third project I was seeing not only genuine interest, but some real engineering thinking and approaches to the problems they were encountering. But this was only possible because I went out and bought all of the components they needed on my own dime because the department didn't have the budget to even have such things as 2n3055 transistors available for students taking a course that included the basics of power amplifiers.

However, having knocked simulation-based education, it wouldn't be fair unless I also take a shot at modern lab courses, too. Many such courses have been reduced to "paint-by-number" projects in which students are guided, step by step, with exactly what to do. Worse, many of the modern test instruments such as oscilloscopes are sophisticated enough that all they ever learn to do is push "Auto Set" and then assume that what they see is what they should be looking at.

 

The key to using a simulator is to understand its limitations and to understand what you are trying to simulate.

The first one is obvious; The 2nd one is more important - our models, not matter how elaborate they are, are never perfect, never 100% accurate, and 100% comprehensive, and in most cases, you don't even have models for the particular devices you are simulating. But that does not matter most of the time - if you had designed a circuit that's so specific to a particular set of attributes, that circuit has no chance to work in the real world.

Many times, all it takes is to understand what the underlying physical behaviors you are trying to simulate, and design a circuit that reproduces that behavior - I for example have used LTspice to simulate boilers/heaters, insulation, spring and structural dynamics -> because end of the day, they are mathematically the same.