Easy to learn circuit simulator

[Zinger]

I'm a software engineer who has spent his whole life avoiding anything more complicated than 1 and 0.  Now I trying to learn the analog world.

Can anyone recommend a 101 and up tutorial for LTSPICE or other freeware circuit simulators?  Where should I start?  My immediate interest is building a logic level circuit that can control a 12V 5A load.

I actually found something that looks like exactly what I need on a UK Vaping site.  But I'd really like to know what I'm doing before trusted vape modifier a 1/4 of the world away.

[ebclr]

http://everycircuit.com/

[Dubbie]

As a simulation noob, I found LTSpice super simple to learn and use. The UI looks about 20 years out of date, but everything works fine.

And best of all the results agreed with reality, So I know I was doing something right.

[tautech]

I'm a software engineer who has spent his whole life avoiding anything more complicated than 1 and 0.  Now I trying to learn the analog world.

Can anyone recommend a 101 and up tutorial for LTSPICE or other freeware circuit simulators?  Where should I start?  My immediate interest is building a logic level circuit that can control a 12V 5A load.

I actually found something that looks like exactly what I need on a UK Vaping site.  But I'd really like to know what I'm doing before trusted vape modifier a 1/4 of the world away.

There's some recommendations here:
https://www.eevblog.com/forum/beginners/circuit-simulation-(sticky)/

[TheAmmoniacal]

Don't forget the Falstad Circuit simulator! It might just look like a toy or a game, but it's quite useful when you're just starting to learn.

http://www.falstad.com/circuit/

[Zinger]

Thanks everyone.  The LTSpice links are very helpful and Falstad had a template that almost exactly matched the circuit I was looking at.  I just added a resistor across gate and source to keep the MOSFET from floating.

Now I have to dig in enough to make sure I understand everything before breaking out the soldering iron.

I really love forums like this one and all the people posting how-tos and DIY stuff on YouTube. 

[Ratch]

I'm a software engineer who has spent his whole life avoiding anything more complicated than 1 and 0.  Now I trying to learn the analog world.

Can anyone recommend a 101 and up tutorial for LTSPICE or other freeware circuit simulators?  Where should I start?  My immediate interest is building a logic level circuit that can control a 12V 5A load.

I actually found something that looks like exactly what I need on a UK Vaping site.  But I'd really like to know what I'm doing before trusted vape modifier a 1/4 of the world away.

Check out this site, https://www.systemvision.com/ , and look at the 2 minute video "SystemVision in 5 easy steps".  I was impressed, and I think you will be, too.  Best of all, it's free for nothing.  Let us know what you think.

Ratch

[TheAmmoniacal]

I'm a software engineer who has spent his whole life avoiding anything more complicated than 1 and 0.  Now I trying to learn the analog world.

Can anyone recommend a 101 and up tutorial for LTSPICE or other freeware circuit simulators?  Where should I start?  My immediate interest is building a logic level circuit that can control a 12V 5A load.

I actually found something that looks like exactly what I need on a UK Vaping site.  But I'd really like to know what I'm doing before trusted vape modifier a 1/4 of the world away.

Check out this site, https://www.systemvision.com/ , and look at the 2 minute video "SystemVision in 5 easy steps".  I was impressed, and I think you will be, too.  Best of all, it's free for nothing.  Let us know what you think.

Ratch

If you work for SystemVision, just disclose it

[Ratch]

I'm a software engineer who has spent his whole life avoiding anything more complicated than 1 and 0.  Now I trying to learn the analog world.

Can anyone recommend a 101 and up tutorial for LTSPICE or other freeware circuit simulators?  Where should I start?  My immediate interest is building a logic level circuit that can control a 12V 5A load.

I actually found something that looks like exactly what I need on a UK Vaping site.  But I'd really like to know what I'm doing before trusted vape modifier a 1/4 of the world away.

Check out this site, https://www.systemvision.com/ , and look at the 2 minute video "SystemVision in 5 easy steps".  I was impressed, and I think you will be, too.  Best of all, it's free for nothing.  Let us know what you think.

Ratch

If you work for SystemVision, just disclose it

For what purpose?  I don't, but I wish I did.  You can't beat the price.  I just love the unlimited voltage and current  scope probes that can be attached anywhere to the circuit.

Ratch

Ratch

[ebclr]

Thanks that Systemvision is amazing.

But since is very powerful and free, one question arise who pays for that, from where the monetization comes from?

[Ratch]

Thanks that Systemvision is amazing.

But since is very powerful and free, one questions arise who pays for that, from where the monetization comes from?

If you read all the material on the site, you will see that they have an enhanced software version that is useful for production and professional engineers.  That does co$t.  However, the free version does a hell of a lot, and is worth a careful perusal.  Besides, it is actually fun to use.  Be sure to study all the tutorials and be further amazed.  Everyone interested in circuit simulation should check this program out.  There is no trial time limit.

Ratch

[darrellt]

I'm responsible for SystemVision at Mentor Graphics (A Siemens Business).  AMA!

SystemVision Cloud is a straightforward SaaS product -- we provide a high degree of functionality for FREE with the goal of developing a community of enthusiastic and satisfied users. We are upfront and transparent about also offering paid subscriptions that provide more capabilities. 
(We have some pretty cool features for workgroup collaboration, for example, that require a subscription).
You can see our subscription offerings: https://www.systemvision.com/subscriptions
There's nothing tricky here. This is a lot like github, but for circuit design, modeling, and simulation.

We expect that the vast majority of users in the community will use the free version, and that we must continually improve this version to maintain the trust and endorsement of this community.

[Howardlong]

If you have a tablet, I strongly recommend NI's Multisim Touch, it's the only circuit simulator I use, being a Luddite in the simulator field, and too many years of managing perfectly well without such tools! While I'm sure it's not as fully featured as some, it's crazy simple to use if you want to try a concept out quickly.

[kripton2035]

this one is not free, but only $10 and is really nice user interface
http://icircuitapp.com/
works on mac,win,phones

[rstofer]

I'm going to vote for LTSpice because it is the only system I have used since I last used the IBM Circuit Analysis Package back in college (circa '73).  Punched cards...

For the beginner, I'm not sure circuit simulation is even a good idea.  It's sort of like getting the wrong answer to 12 digits.  The simulation isn't the real circuit.  The whole point of design is to know how it's going to work and why it's going to work and then seeing if the simulation agrees.

A 12V 5A control, driven from a logic circuit seems like it just calls for a logic level MOSFET, or a relay with a transistor relay driver.

https://www.sparkfun.com/products/10213

The bildr tutorial is worthwhile and the datasheet claims well over 40A with a 5V gate.

If the MOSFET gets warm, add a heatsink.  I'm not sure how to add the heatsink to LTSpice.

Sometimes it just comes down to Ohm's Law and a couple of graphs.  See page 3 of the first datasheet.  Print the page and plot the 5A operating current on Figures 1..3.  Check against the logic voltage (I would assume 4V from a 5V Arduino).

Work out the power dissipation from RdsON and the load current.  I make the resistance about 0.03 Ohms and with 5A, that comes out to 3/4 Watt.  It could be 0.04 Ohms with a 4V Vgs, so maybe 1W.  Just the power version of Ohm's Law.

Nevertheless, LTSpice is a pretty fantastic piece of software.

[NivagSwerdna]

I'm trying to model a simple 2N7000 or BSS138 as a switch...

I tried PartSim, drawn with the stock MOSFET and it worked... but when I try to select a known model e.g. 2N7000

I get "partsim too many parameters for subcircuit type"

So... thought I would try SystemVision...

MOSFET from Datasheet

But no stock parts... do I really have to type all the numbers in?

If I could get it to work both look good... PartSim a bit simplier.

(I've had luck with TinaTI and LTSpice too in the past.)

[john_c]

I'm responsible for SystemVision at Mentor Graphics (A Siemens Business).  AMA!

SystemVision Cloud is a straightforward SaaS product -- we provide a high degree of functionality for FREE with the goal of developing a community of enthusiastic and satisfied users. We are upfront and transparent about also offering paid subscriptions that provide more capabilities. 
(We have some pretty cool features for workgroup collaboration, for example, that require a subscription).
You can see our subscription offerings: https://www.systemvision.com/subscriptions
There's nothing tricky here. This is a lot like github, but for circuit design, modeling, and simulation.

We expect that the vast majority of users in the community will use the free version, and that we must continually improve this version to maintain the trust and endorsement of this community.

You need to fix the terms of service link on the sign-up dialog box.

The part that matters to me is the following: "you retain all ownership rights that you have in your submission."

[darrellt]

Yes, you are right, there is an incorrect "terms of service" link in the sign-up page. Thanks for pointing it out!
Here is the correct link: https://www.systemvision.com/terms-of-use, which it appears that you found at the bottom of each page.

And you are correct, it clearly states that "you retain all ownership rights that you have in your submission."

[darrellt]

Did you discover the tools for create parts from datasheets?  It's in the upper left corner of the schematic.
Create New Component -> From Datasheet

You still need to type in values, but it makes things more convenient and it will save the model in your "My Components" area of the palette.

[steverino]

As a software engineer in a prior life, I come from a similar background.  I've tried falstad, ltspice and multisim.  By far, multisim was the best in terms of ease of use.  It's a great tool when learning electronics.  It only takes minutes to enter a circuit and test the results.  Caveat: It's good to always breadboard the circuit afterwards and see if the simulated behavior is correct.  Luckily, I happened to run across an educational license key   on the web which allows me to use the education version.  So right now, the cost to me is $0.  Anybody know if NI offers educational versions to non professional, non students?

Edit: Multisim seems to be offering to a cloud based system.  Check out the site beta.multisim.com.  I just ran across the web site recently and haven't checked it out.  I hate cloud based tools for obvious reasons.