Circuit simulator software for beginners

dl324

Joined Mar 30, 2015
13,277
Welcome to AAC!
Thanks SamR. I am very new here. I'll check it out. Thanks again.
+1 for LTspice.

Simulators have their place, but I suggest that you learn the fundamentals before relying on a simulator. Otherwise, you run the risk of becoming too dependent on the simulator and not being able to design circuits without one.

I'm old school. I like to use the simulator between my ears. If I'm too lazy to breadboard the circuit, or don't have the parts, I'll run a simulation. I haven't used LTspice enough to be able to use it's capabilities well. I once tried simulating a linear regulator being used as a switching regulator and LTspice was very picky about the component values that would work and was overly pessimistic on switching noise. When I breadboarded the circuit, all component values I tried that wouldn't simulate worked and output ripple was significantly lower.

For digital, I use Digital Works, it's free from here. It has its limitations and is no longer being maintained, but the price is right and I only recall encountering one unreproducible bug. I use it for the same reasons I use LTspice.
 
Last edited:

Thread Starter

James Tomy Abraham

Joined Sep 23, 2021
14
Welcome to AAC!
+1 for LTspice.

Simulators have their place, but I suggest that you learn the fundamentals before relying on a simulator. Otherwise, you run the risk of becoming too dependent on the simulator and not being able to design circuits without one.

I'm old school. I like to use the simulator between my ears. If I'm too lazy to breadboard the circuit, or don't have the parts, I'll run a simulation. I haven't used LTspice enough to be able to use it's capabilities well. I once tried simulating a linear regulator being used as a switching regulator and LTspice was very picky about the component values that would work and was overly pessimistic on switching noise. When I breadboarded the circuit, all component values I tried that wouldn't simulate worked and output ripple was significantly lower.

For digital, I use Digital Works, it's free from here. It has its limitations and is no longer being maintained, but the price is right and I only recall encountering one unreproducible bug. I use it for the same reasons I use LTspice.
Thanks for the response. I have some experience in troubleshooting electronic circuits but not in design. Perhaps you could tell me from where I can get the fundamentals right. I downloaded LTSpice XVII and found another in the Microsoft Store called DrawLogix. I need to take the learning and the simulation together, a bit of reverse engineering to help me along the way.

Thanks for the inputs. I owe you guys.
 

SamR

Joined Mar 19, 2019
3,531
There is a bit of a learning curve getting started with LTS and more to become truly proficient at it. Which I am not. It's kinda funky at first but it grows on you. It does not produce "standard" schematics but what it does do is pretty amazing.
 

dl324

Joined Mar 30, 2015
13,277
Perhaps you could tell me from where I can get the fundamentals right.
Nothing is going to beat learning it in a school setting. You need someone giving you the theory, in a logical order, and being able to tell when you're not getting it; either through tests or looking at your eyes gloss over from confusion.

Some people can self teach, but the vast majority will need a more formal education.

If you use YouTube videos and the internet for your information, you'll be at a serious disadvantage because you won't likely be able to tell the difference between what's good and what's bad. There are a lot of YouTube videos that supposedly explain things at a glacial pace when, in reality, they don't know much and are just trying to monetize your time.
 

Thread Starter

James Tomy Abraham

Joined Sep 23, 2021
14
There is a bit of a learning curve getting started with LTS and more to become truly proficient at it. Which I am not. It's kinda funky at first but it grows on you. It does not produce "standard" schematics but what it does do is pretty amazing.
Ok SamR. I'll see how it goes.
 

Thread Starter

James Tomy Abraham

Joined Sep 23, 2021
14
Nothing is going to beat learning it in a school setting. You need someone giving you the theory, in a logical order, and being able to tell when you're not getting it; either through tests or looking at your eyes gloss over from confusion.

Some people can self teach, but the vast majority will need a more formal education.

If you use YouTube videos and the internet for your information, you'll be at a serious disadvantage because you won't likely be able to tell the difference between what's good and what's bad. There are a lot of YouTube videos that supposedly explain things at a glacial pace when, in reality, they don't know much and are just trying to monetize your time.
Ok dl324, I do have a formal education but no practical experience in designing. I don't need to be a designer but I want to study schematics to understand how each component functions in the circuit. That at the moment, helps me with troubleshooting faulty PCBs and later, design if I get good at it.
 

dl324

Joined Mar 30, 2015
13,277
Ok dl324, I do have a formal education but no practical experience in designing.
Depending on how many years it has been since you took classes and how much practice you've had since then, you may have a lot of review ahead of you. I didn't do much coding for a few years after I retired and was shocked, and disappointed, with how much I had forgotten. It seemed like it took forever to get back to anywhere near the level I was at when I used those skills daily; though it was probably more like 3-6 months. It was frustrating as all get out to have to relearn how to do things I knew I used to be able to do (kind of like what Microsoft does to me with every OS release).

That being the case, my suggestion would be to force yourself to try to remember what you learned and only use the simulator for circuits that you can't analyze by yourself. Then use the simulation results to improve your understanding.

I switched to computers and software a few years after I graduated. I didn't design many circuits of my own for several decades. When I got back to it, I didn't have to do anywhere near as much review as I did for C, Perl, sed, csh, ... I'm not at the same level of competency as when I first graduated, but I don't need much of the underlying theory to do what I want to do.
 
I was kinda odd, that I managed an AAS degree in Electronics Technology and did not have a course in OP amps.
Seemingly impossible, but yea. I also graduated in another degree program while on a leave of absence. Probaby the real killer is that I took two classes as a "ghost". At one point, I was offered, but turned down to have my entire college record totally erased and start over. I did not choose that option.

Those few points that you "need" for OP-amps don't seem to exist anywhere. The non-ideal behavior is what gets you in total trouble. I had one circuit that I designed and made a PCB for and it was part of a $5000.00 USD instrument that I was building. It used two system DVM's, a quad voltage source+digital outputs, all IEEE-488 controlled.

Glitch #1.
Our calibration devices that this device had to connect too, had too much capacitance, so I had to isolate the capacitance of the device. 3 circuits needed major changes.

Glitch #2
I thought I really blew it. I had no other person to turn too. I needed a 200 ohm resistor for the bias current to have a place to go. A few pA across 0.001 ohms is still a lot of current. A few pA across 200.001 ohms is much better.

Glitch #3, never really got fixed.
I was trying to remove an offset by solving 2 simultaneous equations with the instrument in two configurations.
BUT I forgot that 0V out from the D/A converter was not ZERO. I needed a true zero for it to work and I didn't divie down the +-1V to say +-10mV.

I got excellent AC performance and that was the goal. DC performance was icing. I had no other way of fixing the offsets, but the current offset was 40pA. The DC offset was a few mV. Both pretty respectable.

I used these cute power bricks (I think three +-15V and one 12Vdc) from analog devices. I think I used 4 of them.
Not exactly sure how I would make the instrument today. The power supplies were critical.

Glitch #5
Not really a glitch, but I really need to understand front end FET circuits for electrometer OP-amps.
 

Audioguru again

Joined Oct 21, 2019
3,632
Beware that simulation software use models that have "typical" specs. The circuit might fail with devices that have minimum or maximum specs.
Also, the software does not check for extremely overloaded parts or much too much heating.
 

Thread Starter

James Tomy Abraham

Joined Sep 23, 2021
14
Depending on how many years it has been since you took classes and how much practice you've had since then, you may have a lot of review ahead of you. I didn't do much coding for a few years after I retired and was shocked, and disappointed, with how much I had forgotten. It seemed like it took forever to get back to anywhere near the level I was at when I used those skills daily; though it was probably more like 3-6 months. It was frustrating as all get out to have to relearn how to do things I knew I used to be able to do (kind of like what Microsoft does to me with every OS release).

That being the case, my suggestion would be to force yourself to try to remember what you learned and only use the simulator for circuits that you can't analyze by yourself. Then use the simulation results to improve your understanding.

I switched to computers and software a few years after I graduated. I didn't design many circuits of my own for several decades. When I got back to it, I didn't have to do anywhere near as much review as I did for C, Perl, sed, csh, ... I'm not at the same level of competency as when I first graduated, but I don't need much of the underlying theory to do what I want to do.
I never did practice while I was in college. I have a degree in Applied Electronics and Instrumentation but the fact is I was forced into college, dropped out and went back again. Never interested in the college lab and somehow managed to pass exams just for the sake of having the degree. But things changed when I got a job in maintenance. I had problems that needed a solution. I was interested in getting into the specifics. Faced plenty of electronic faults and realized it was a black box for many. Since then I have attempted to understand each circuit I came across - mostly power supplies, welding inverters, valve driver, common appliance controls etc. Therefore, I like to understand design, just to understand how the circuit functions.

Thanks for the suggestions. My current plan is to interpret schematics and understand basic function. The details can fit in later.

Cheers.
 

dl324

Joined Mar 30, 2015
13,277
Never interested in the college lab and somehow managed to pass exams just for the sake of having the degree.
I don't want to rain on your parade, but not being interested in what you were learning, only doing enough to pass tests, and never working with what you learned to help it sink in doesn't bode well for you recalling what you were taught.

I've known a number of people who got better grades than me in school, but many of them managed to do that without learning anything. When I was studying electronics, I was always on the dean's list for my grades, but that didn't mean as much to me as learning something that I could use to earn a decent living.
 

Thread Starter

James Tomy Abraham

Joined Sep 23, 2021
14
I don't want to rain on your parade, but not being interested in what you were learning, only doing enough to pass tests, and never working with what you learned to help it sink in doesn't bode well for you recalling what you were taught.

I've known a number of people who got better grades than me in school, but many of them managed to do that without learning anything. When I was studying electronics, I was always on the dean's list for my grades, but that didn't mean as much to me as learning something that I could use to earn a decent living.
Yeah. I can't recall anything I've been taught but my profession helped me to learn some stuff and it helps me to be motivated to learn about electronics.
 
Top