I appreciated that smoke comes out of the battery if you short it :)
Edit: I am ex EE. I will note that it's horrible using this view. It is marginally more horrible than using breadboards in reality. Schematics exist because reality tends to suck or have inconsistencies. For example TO-99 packages come in different pin orders, so 2N3904 has the opposite order to a BC547. Also breadboards tend not to have full length bus bars depending on vendors. At least though in this form it's an ideal representation though which doesn't have parasitic capacitors, inductors, dodgy contacts and no ground plane all over it.
Ah this reminds me of my first big mistake with PCBs. I have recently started down the hardware track, and my first PCB has a number of BC547 and BC558 transistors on it.
Once I had a functioning prototype, the next step was to convert it into a schematic. After that, you have to convert the schematic into a PCB. Now we are at two layers of translation, and at this step I made a mistake: I wanted to use SMD components to save money, and I found that the BC8xx transistors are the SMD equivalent of the BC5xx ones, so I used the footprint of the BC8xx transistors in my PCB, with no errors from KiCad.
As it turns out, the BC8xx footprint is not compatible with a BC5xx schematic! The pinout is different: the base is pin 1 instead of pin 2, so the components in my PCB that use transistors (crucially, the voltage controlled amplifier) didn't work. Unlike a bug, that mistake cost me $200 and weeks of development time, but after 10+ years of writing software I'm still happy to be making things that people can touch.
Mine was assuming that the stripe on tantalum SMD capacitors was the negative side. First prototype board came back from the fab and pick and place department (we had it in house). Immediately caught fire when I powered it up :)
Second lesson, start with current limit on your bench supply, not throw 10A into it :)
You can catch it with a footprint review. List all your new footprints or old footprints assigned to new parts, and have someone else check them against the datasheets. Or if you ever have the good fortune to work with a very good layout designer, they will check things like that for you just to catch you out.
Write a list of everything that you fuck up every time, check the next one against it and eventually you get a good one first hit. I had three in a row that worked out of the box in the end!
Printing the board outline and layers combined as well. And checking you used the correct footprints against actual parts helps.
Schematics also help explain your circuit because the idioms of drawing them communicate intent. Which is one of the things the Shenzhen/Ladyada/Sparkfun/SeedStudio crowd don't get with their "schematic as data entry for layout" style. Some of them should know better.
Breadboards make me wince a little especially in a professional setting but I've made my peace with dev boards that come with DIP-style pins for them. Decent breadboards are so cheap now that every dev board get to live on its own permanent breadboard.
> Schematics also help explain your circuit because the idioms of drawing them communicate intent.
I think this is a key point. One could imagine three layers:
(1) NETLIST: a list of text-only descriptions, like "R1 1 0 1k", or even a sentence description "connect a 1k resistor between node 1 and node 0"
(2) SCHEMATIC: a 2D drawing with canonical symbols, straight lines for wires, and labels/notes
(3) LAYOUT: a 3D (or multi-layer 2D) physical representation for PCB, or in this case breadboarding
All three layers are useful. (Obviously you need layout to make a PCB, and you need a netlist for simulation.)
But for most humans, where we have 2D visual representations baked in, if you're trying to understand or communicate what's going on:
- It's really really hard to keep track of a bunch of text sentences like a netlist and node numbers/names for all but the simplest circuits -- maybe 3-5 elements?
- It's really really hard to follow a 3D layout of PCB tracks that leads to pads, and then having to remember pin orders etc.
- It's easiest to follow a schematic diagram. It's browsable. It contains "idioms", as you say, about signal flow, logical block groupings, etc.: purpose and intent and functionality, in a way that netlists and physical layouts don't.
FYI, for medium-large digital circuits, I don't think this is true: probably just reading VHDL/Verilog, like reading source code, makes more sense. This is closer to the "netlist" level. I think that's because you'd name modules and inputs/outputs in a way similar to how you'd name functions and arguments in software, which doesn't really apply to "Resistor" or "Capacitor" as primitives.
But for a pretty big practical range of mixed-mode and analog things, I'd argue that schematics really are the easiest level for our brains.
(Disclosure: I'm one of the founders of CircuitLab https://www.circuitlab.com/ (YC W13) where we've been building an online circuit simulator & schematic editor for a long time. Although I'm mostly on the simulation engine / netlist side. My cofounder and other teammates have done most of the schematic GUI work.)
IMHO solderless breadboards still have their place for prototyping some slow circuits, ballpark maybe < 1 MHz signals, if you're aware of the extra capacitance and limitations. :)
You essentially can practice the classical art of memory on a 2D representation (think why you can remember who was at lunch by thinking about where they sat), and it's useful to have them at different levels. Almost any nontrivial schematic should have an associated block diagram (by this I do not mean it necessarily should be captured at the block diagram level in a "hierarchical design"; these can be more trouble than they're worth). There are other types of diagrams that can be useful, too.
I haven't done much HDL work so I don't have strong opinions there, but let's think about graphical representations source code and software intent for a moment. I like to see some block-level description of firmware even if it's just a few rectangles representing the main loop and each ISR other other process with text indicating what they do. I like to see statecharts. If someone has written an implicit flags-and-conditionals state machine, I'll draw the statechart and start probing for bugs and debugging from there. Tools like Scitools Understand are drastically underrated for figuring out other people's code, incidentally.
What kills me about the aforementioned style is that it eschews the schematic as a tool for thinking and implicitly sees schematic capture as a layer of friction you have to get through to get to layout. I suspect a lot of designs drawn that way were built up point-to-point on a breadboard and never sketched or even otherwise mentally visualized.
I mean when they put parts down on the schematic and just attach net names to them. You know, the pull-up resistors in the corner with named nets on them, not shown attached to particular pins or buses. Usually with a dotted box drawn around them. Frequently horizontal.
Also usually totally implicit power routing. And no one that draws schematics that way has ever learned the value of drawing IC symbols to fit the circuit as opposed to the physical pinning of the device.
Steam: 78% positive reviews out of 675. $8.99. Windows-only, though the website says “CRUMB is available for iOS and Android along side its desktop counterparts on Windows and MacOS.”
Looks great, but pretty difficult to work with. Would be nice to be able to switch to top view to see more clearly where you're plugging things.
Edit: Clicking the background and dragging it actually gave me the top view I was looking for. Thank you goodcanadian.
That said, I still think this application is a better skillset demo than a practical tool to use.
Not a fan. The standard schematic abstraction is great and actually helps us parse circuits.
Don't add unnecessary complexity just because AIs are good at vibecoding threejs demos (edit: even if this particular demo seems to predate vibecoding and was likely used for training instead of being the product of inference).
For me there seems to be a listing of configurable settings or something but it only pops up for a single frame after I right-click-drag a component - this seems like a broken mouse interaction.
On the contrary, when I was in high school we had one class dedicated to digital electronics and it revolved around breadboard circuitry. You only had 30 minutes/day to tinker with the physical hardware then it had to be disassembled for the next class. Simulations like this are more approachable then schematics and would have been great for tinkering outside of class.
When I was a small child it was cool to play with circuitry (dad did some electronics) but as soon as I encountered components of different shape (a capacitor that looks like a resistor) it stopped making sense to me. thinking in schematics early is key
I'll grant you the vibecoding comment. That was uncalled for and unjustified.
From an EE perspective I still see limited value in having a 3D breadboard. Having a standardized schematic language is really nice. Everybody knows how resistors, capacitors and transistors look like in a schematic, whereas they are all just little cuboids with varying number of pads in their smd packages. I recommend multisim blue for learning btw.
Nevertheless, a cool project and I should be more positive when commenting.
Is there a good free circuit simulator (that use a schematic as interface, I assume)?
I somewhat agree with you in general though—if the web UX is a breadboard… maybe just get a breadboard? At the same time, while physical parts are generally cheap enough, power supplies, multimeters, an oscilloscope… that part of the hobby can add up.
Sometimes too I am waiting a week or two for a part to arrive from Mouser, it is nice to be able to mock up a circuit online.
I've found a combination of circuitjs and a spice simulator to be quick for prototyping custom analog circuits (made mainly from discretes). Circuitjs https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators, but with the tradeoff of convergence issues for more complex circuits, so I use circuitjs as a playground then use LTspice as a rigorous simulator.
If it's a circuit made by composing multiple integrated circuits based on their application notes and not a custom analog design, I just use LTspice alone since you can just import the manufacturers spice behavioral model (assuming they didn't encrypt them...)
There are many. What's your (computing) platform and what are you trying to simulate?
The more professional tools (beginning with freebies like LTspice) are oriented around letting you probe waveforms from simulated inputs and are not as oriented towards interactive probing "does this LED light when I press that button?" as a hobbyist might want.
I personally reach for LTspice from Analog Devices first even if I have better available - it is quick, easy enough to use, and someone has ported the model you need to it already. There is a Mac version on their web site but I have never used it.
Micro-Cap is free-as-in-free-beer but windows-native and will do stability analysis (gain margin/phase margin).
Qucs-S + the backend simulator of your choice is probably your best bet for free software on Mac. Original Qucs is still developed (checkins last month on their github, if you want to try building from source) but hasn't had a release in almost ten years. QucsStudio is now uSimmics and is closed-source and Windows-native. They all have their peculiar uses. I haven't used any of them much.
Online you can use PartsQuest Explore for free for public designs and short simulation runs. I have not used the online version much but it is basically the very powerful Siemens (Mentor) VHDL-AMS simulator that has gone by a number of names (Mentor never commits to names) on the backend. I have used that: it came with PADS Standard Plus. It surprisingly does just about everything at least usably well. It can use spice models or VHDL-A(MS) models. It can use RF s-parameter models. It can use control-theory laplace-transform block models. It will do stability analysis and monte carlo analysis. It can run VHDL models. You can model just about anything you can write the ODEs for in VHDL-AMS: try viewing source on their motor model for example. You won't get the filter synthesis or analysis tools you'll find in a dedicated RF simulator like Keysight Pathwave. You won't get the controls design and analysis tools in the Matlab/Simulink toolkits. But it does a whole heck of a lot.
There are tons of free sim tools. 'Spice' (Simulation Program with Integrated Circuit Emphasis) was a very early commercial sim. So many of the free ones use some variant of spice in their name. LTSpice, Qspice, etc.
Kicad is an excellent free schematic capture and simulation software.
I don't think the vibecoding jab is warranted, but I agree this is a pretty terrible UI for electronic circuits. Schematic capture exists for a reason! It's not even difficult for beginners to understand if you have a decent UX (which for some reason seems to elude 90% of PCB software).
Got to agree. This is kind of pointless. Breadboards exist to make it easier to build physical circuits. I would also argue there is paedagogical value in actually playing with a physical breadboard. Having to physically orient things in 3D space is a small price you pay for building a physical prototype. This is all the downsides with none of the upsides.
This is so damn cool. I remember 10-12 years ago i used to teach kids to do these things manually. This is a great product for kids to experiment and then run it real life on their kits.
I feel like the fade-in animation when starting/stopping the simulation takes too long. Also, I think it would be helpful if the currently connected row was highlighted when dragging a pin.
I'm working on a similar project, it's called schematik.io and you can use it to generate hardware projects (schematics, components lists, code, everything). Love the 3d viewer they've done here.
Are there similar solutions without 3d view? I want to get a simulator that can show me what is going in the circuit, ideally slowed down a lot. For example I was making a dongle with resistor and capacitor which was delivering a pulse-short (i.e. removing power for a short period of time instead of delivering an impulse) and while I was able to confirm overall idea with some online simulator, dialing in capacitance and resistance required physically switching components. Ideally I want to be able simulate such transient effects and arrive at specific numbers ready to be soldered.
orcad is the commercial classic for doing schematics with a spice backend. (spice is an oss engine out of berkeley for simulating circuits on computers. for dc it just solves the classic nodal analysis and for ac you can feed in things from a fantasy signal generator and capture things at various nodes in the circuit) there's also some pretty cool looking commercial web thing now that also will maintain netlists with real-time prices and will let you swap parts out and set minimum quantities etc.
kicad is the oss orcad, but i never got good at it. (to be fair, orcad was weird to learn as well)
I think altium has taken over as the top tier commercial offering in this space.
I always disliked Orcad. Especially because cadence had excellent software that predated OrCAD, and for reasons that I cannot fathom chose to promote OrCAD after they acquired it instead of the better software.
Here's a specific example in the interface. If you wanted to draw a wire, the keyboard shortcut of the old software was 'w' but orcad required you to type 'ctrl + w'. Why are you forcing me to use control when w doesn't do anything on its own? It was filled with similar tiny annoyances that just slowed things down. (Admittedly, it's been years since that was my primary work, and free stuff is good enough for what I do now.) I sincerely hope that orcad has continued to improve over the years.
Altium has taken over a lot of small to medium sized shops. Mostly because the price is right for its capability. It also has a history of being the least bad compromise between the odd mixtures of excellence and user-hostility Cadence and Mentor tend to come up with, going back to the Protel days, and they've done a good job in the last decade+ of marketing it to those shops. Cadence and Siemens nee Mentor (and maybe Zuken? I've never seen Zuken in the wild, but it always makes these lists) have been neglecting the entry level and smaller organizations and aggressively trying to move their customers to their higher tier offerings during that time. But while it's Altium's flagship product, it is not top tier. It is really entry-level for a professional PCB-level design package, like PADS and OrCAD as opposed to Xpedition and Allegro.
Years ago, around 10-12 years back, our Windows XP PC had software similar to this. Dont remember the name. I used to spend hours experimenting with it. haha Nostalgia.
This would be useful for opensource hardware projects (aimed at beginners) to literally see how things are wired together. I'm still not at the schematic phase myself. But I use MS Paint wiring diagrams.
Yeah that is still on my list to learn eg. designing my own circuit board. My stuff is still basic eg. wiring together an Arduino/RPi to break out sensor boards.
Nice! You can play Electroboom without actually getting shocked. If you do want the real world experience you can get bags full of components on Amazon for pretty cheap
The simulation needs an "Amazon factor" slider, which randomly makes:
* All breadboard wires have some resistance
* Some breadboard wires have very high resistance
* Some breadboard wires have intermittent contact, recalculated every time components are added/removed from the breadboard
* Some fraction of polarized capacitors are backwards
* All capacitors are overrated for voltage and explode at 70-99% of their rating
* Some LEDs smoke at 10% of their rated forward current
* Brightness variation between LEDs that should be identical
* Semiconductors may randomly be another semiconductor in the same class (e.g. a "2n2222" may in fact be any other NPN BJT in the simulation, or the parameters may be entirely random)
* Inductors have 80% variation in core saturation specs, but other parameters are spot-on
* Any component with writable flash (eg USB vid/pid strings) may randomly not actually have writable flash but instead fixed strings and the writes fake success but the values do not change
Better simulators can do parameter sweeps and monte carlo simulations so you can explore tolerance stackup issues. But most of the failure modes you've listed there are just why you shouldn't build your circuits for one on breadboards and for another with dodgy parts sourced outside of distribution channels.
There used to be some really good web-based SPICE interpreters but I can't find them now. This was before javascript ate everything, so you would enter the netlist, click a button, and get a GIF or the current at a specified terminal or whatever
I appreciated that smoke comes out of the battery if you short it :)
Edit: I am ex EE. I will note that it's horrible using this view. It is marginally more horrible than using breadboards in reality. Schematics exist because reality tends to suck or have inconsistencies. For example TO-99 packages come in different pin orders, so 2N3904 has the opposite order to a BC547. Also breadboards tend not to have full length bus bars depending on vendors. At least though in this form it's an ideal representation though which doesn't have parasitic capacitors, inductors, dodgy contacts and no ground plane all over it.
It is good fun though :)
Ah this reminds me of my first big mistake with PCBs. I have recently started down the hardware track, and my first PCB has a number of BC547 and BC558 transistors on it.
Once I had a functioning prototype, the next step was to convert it into a schematic. After that, you have to convert the schematic into a PCB. Now we are at two layers of translation, and at this step I made a mistake: I wanted to use SMD components to save money, and I found that the BC8xx transistors are the SMD equivalent of the BC5xx ones, so I used the footprint of the BC8xx transistors in my PCB, with no errors from KiCad.
As it turns out, the BC8xx footprint is not compatible with a BC5xx schematic! The pinout is different: the base is pin 1 instead of pin 2, so the components in my PCB that use transistors (crucially, the voltage controlled amplifier) didn't work. Unlike a bug, that mistake cost me $200 and weeks of development time, but after 10+ years of writing software I'm still happy to be making things that people can touch.
We've all done that sort of stuff!
Mine was assuming that the stripe on tantalum SMD capacitors was the negative side. First prototype board came back from the fab and pick and place department (we had it in house). Immediately caught fire when I powered it up :)
Second lesson, start with current limit on your bench supply, not throw 10A into it :)
I've been an EE for a decade and I made this exact mistake last week. It's inevitable lol
You can catch it with a footprint review. List all your new footprints or old footprints assigned to new parts, and have someone else check them against the datasheets. Or if you ever have the good fortune to work with a very good layout designer, they will check things like that for you just to catch you out.
I haven't managed to design a pcb without finding an issue in the first run.
Shoutout to OSHpark's prototype service. Something like 5 bucks an inch and you only have to toss out 3 if you find a fault.
Write a list of everything that you fuck up every time, check the next one against it and eventually you get a good one first hit. I had three in a row that worked out of the box in the end!
Printing the board outline and layers combined as well. And checking you used the correct footprints against actual parts helps.
Schematics also help explain your circuit because the idioms of drawing them communicate intent. Which is one of the things the Shenzhen/Ladyada/Sparkfun/SeedStudio crowd don't get with their "schematic as data entry for layout" style. Some of them should know better.
Breadboards make me wince a little especially in a professional setting but I've made my peace with dev boards that come with DIP-style pins for them. Decent breadboards are so cheap now that every dev board get to live on its own permanent breadboard.
> Schematics also help explain your circuit because the idioms of drawing them communicate intent.
I think this is a key point. One could imagine three layers:
(1) NETLIST: a list of text-only descriptions, like "R1 1 0 1k", or even a sentence description "connect a 1k resistor between node 1 and node 0"
(2) SCHEMATIC: a 2D drawing with canonical symbols, straight lines for wires, and labels/notes
(3) LAYOUT: a 3D (or multi-layer 2D) physical representation for PCB, or in this case breadboarding
All three layers are useful. (Obviously you need layout to make a PCB, and you need a netlist for simulation.)
But for most humans, where we have 2D visual representations baked in, if you're trying to understand or communicate what's going on:
- It's really really hard to keep track of a bunch of text sentences like a netlist and node numbers/names for all but the simplest circuits -- maybe 3-5 elements?
- It's really really hard to follow a 3D layout of PCB tracks that leads to pads, and then having to remember pin orders etc.
- It's easiest to follow a schematic diagram. It's browsable. It contains "idioms", as you say, about signal flow, logical block groupings, etc.: purpose and intent and functionality, in a way that netlists and physical layouts don't.
FYI, for medium-large digital circuits, I don't think this is true: probably just reading VHDL/Verilog, like reading source code, makes more sense. This is closer to the "netlist" level. I think that's because you'd name modules and inputs/outputs in a way similar to how you'd name functions and arguments in software, which doesn't really apply to "Resistor" or "Capacitor" as primitives.
But for a pretty big practical range of mixed-mode and analog things, I'd argue that schematics really are the easiest level for our brains.
(Disclosure: I'm one of the founders of CircuitLab https://www.circuitlab.com/ (YC W13) where we've been building an online circuit simulator & schematic editor for a long time. Although I'm mostly on the simulation engine / netlist side. My cofounder and other teammates have done most of the schematic GUI work.)
IMHO solderless breadboards still have their place for prototyping some slow circuits, ballpark maybe < 1 MHz signals, if you're aware of the extra capacitance and limitations. :)
You essentially can practice the classical art of memory on a 2D representation (think why you can remember who was at lunch by thinking about where they sat), and it's useful to have them at different levels. Almost any nontrivial schematic should have an associated block diagram (by this I do not mean it necessarily should be captured at the block diagram level in a "hierarchical design"; these can be more trouble than they're worth). There are other types of diagrams that can be useful, too.
I haven't done much HDL work so I don't have strong opinions there, but let's think about graphical representations source code and software intent for a moment. I like to see some block-level description of firmware even if it's just a few rectangles representing the main loop and each ISR other other process with text indicating what they do. I like to see statecharts. If someone has written an implicit flags-and-conditionals state machine, I'll draw the statechart and start probing for bugs and debugging from there. Tools like Scitools Understand are drastically underrated for figuring out other people's code, incidentally.
What kills me about the aforementioned style is that it eschews the schematic as a tool for thinking and implicitly sees schematic capture as a layer of friction you have to get through to get to layout. I suspect a lot of designs drawn that way were built up point-to-point on a breadboard and never sketched or even otherwise mentally visualized.
"…schematic as data entry for layout style…"
Maybe you can explain.
Are you saying in these cases often the physical PCB layout follows the geometry of the schematic?
I mean when they put parts down on the schematic and just attach net names to them. You know, the pull-up resistors in the corner with named nets on them, not shown attached to particular pins or buses. Usually with a dotted box drawn around them. Frequently horizontal.
Also usually totally implicit power routing. And no one that draws schematics that way has ever learned the value of drawing IC symbols to fit the circuit as opposed to the physical pinning of the device.
- click simulate in the default "push button to turn on LED" demo
- clock advances
- voltage around the LED slowly rises to infinity for some reason
er.
I remember following this at the time! FYI it was "shut down" (kept online but no further development) two years ago (https://x.com/KennethCassel/status/1620500575183073280)
> Decided to shutdown Diode. (For now the site is live, I'll likely open-source the code in case anyone wants to take the baton and run)
Kenneth is now working on RMFG (https://www.rmfg.com/)
A more mature version of this is "CRUMB" found on steam, it costs money but it's got a lot of great features.
https://www.crumbsim.com/
Steam: 78% positive reviews out of 675. $8.99. Windows-only, though the website says “CRUMB is available for iOS and Android along side its desktop counterparts on Windows and MacOS.”
https://store.steampowered.com/app/2198800/CRUMB_Circuit_Sim...
No affiliation.
interesting. how does this compare with more "industrial" sims like "proteus" https://www.labcenter.com/simulation/ ?
No affiliation with any. I'm a Comp.E in consumer electronics who likes to keep a pulse on these things.
Looks great, but pretty difficult to work with. Would be nice to be able to switch to top view to see more clearly where you're plugging things.
Looks great, but pretty difficult to work with. Would be nice to be able to switch to top view to see more clearly where you're plugging things.
Edit: Clicking the background and dragging it actually gave me the top view I was looking for. Thank you goodcanadian. That said, I still think this application is a better skillset demo than a practical tool to use.
You can click the background and drag to rotate the view
It's still clunky though. It's a great, cool thing that OP built but just not very practical.
Not a fan. The standard schematic abstraction is great and actually helps us parse circuits.
Don't add unnecessary complexity just because AIs are good at vibecoding threejs demos (edit: even if this particular demo seems to predate vibecoding and was likely used for training instead of being the product of inference).
So we're just using "vibe coded" as a generic insult now for project we don't like?
Well, it somehow gives off vibecoded vibes, even though it's not. Make of that what you want, but that's expressed in quite a few comments here.
Maybe it's just the extremely clean and generic presentation on the website without any links to the author / team / twitter.
For me there seems to be a listing of configurable settings or something but it only pops up for a single frame after I right-click-drag a component - this seems like a broken mouse interaction.
On the contrary, when I was in high school we had one class dedicated to digital electronics and it revolved around breadboard circuitry. You only had 30 minutes/day to tinker with the physical hardware then it had to be disassembled for the next class. Simulations like this are more approachable then schematics and would have been great for tinkering outside of class.
When I was a small child it was cool to play with circuitry (dad did some electronics) but as soon as I encountered components of different shape (a capacitor that looks like a resistor) it stopped making sense to me. thinking in schematics early is key
This is actually very cool and predates vibe coding, please stop gatekeeping.
I'll grant you the vibecoding comment. That was uncalled for and unjustified.
From an EE perspective I still see limited value in having a 3D breadboard. Having a standardized schematic language is really nice. Everybody knows how resistors, capacitors and transistors look like in a schematic, whereas they are all just little cuboids with varying number of pads in their smd packages. I recommend multisim blue for learning btw.
Nevertheless, a cool project and I should be more positive when commenting.
Is there a good free circuit simulator (that use a schematic as interface, I assume)?
I somewhat agree with you in general though—if the web UX is a breadboard… maybe just get a breadboard? At the same time, while physical parts are generally cheap enough, power supplies, multimeters, an oscilloscope… that part of the hobby can add up.
Sometimes too I am waiting a week or two for a part to arrive from Mouser, it is nice to be able to mock up a circuit online.
I've found a combination of circuitjs and a spice simulator to be quick for prototyping custom analog circuits (made mainly from discretes). Circuitjs https://www.falstad.com/circuit/circuitjs.html allows you to edit components live unlike spice simulators, but with the tradeoff of convergence issues for more complex circuits, so I use circuitjs as a playground then use LTspice as a rigorous simulator.
If it's a circuit made by composing multiple integrated circuits based on their application notes and not a custom analog design, I just use LTspice alone since you can just import the manufacturers spice behavioral model (assuming they didn't encrypt them...)
There are many. What's your (computing) platform and what are you trying to simulate? The more professional tools (beginning with freebies like LTspice) are oriented around letting you probe waveforms from simulated inputs and are not as oriented towards interactive probing "does this LED light when I press that button?" as a hobbyist might want.
Thanks. I prefer Mac (maybe preferring online these days though). I do a lot of analog stuff with op-amps lately (analog computing).
I'm breadboarding with physical breadboards but they get messy/cluttered fast, ha ha.
I thought so. I'm a fan of Glider.
I personally reach for LTspice from Analog Devices first even if I have better available - it is quick, easy enough to use, and someone has ported the model you need to it already. There is a Mac version on their web site but I have never used it.
Micro-Cap is free-as-in-free-beer but windows-native and will do stability analysis (gain margin/phase margin).
Qucs-S + the backend simulator of your choice is probably your best bet for free software on Mac. Original Qucs is still developed (checkins last month on their github, if you want to try building from source) but hasn't had a release in almost ten years. QucsStudio is now uSimmics and is closed-source and Windows-native. They all have their peculiar uses. I haven't used any of them much.
Online you can use PartsQuest Explore for free for public designs and short simulation runs. I have not used the online version much but it is basically the very powerful Siemens (Mentor) VHDL-AMS simulator that has gone by a number of names (Mentor never commits to names) on the backend. I have used that: it came with PADS Standard Plus. It surprisingly does just about everything at least usably well. It can use spice models or VHDL-A(MS) models. It can use RF s-parameter models. It can use control-theory laplace-transform block models. It will do stability analysis and monte carlo analysis. It can run VHDL models. You can model just about anything you can write the ODEs for in VHDL-AMS: try viewing source on their motor model for example. You won't get the filter synthesis or analysis tools you'll find in a dedicated RF simulator like Keysight Pathwave. You won't get the controls design and analysis tools in the Matlab/Simulink toolkits. But it does a whole heck of a lot.
There are tons of free sim tools. 'Spice' (Simulation Program with Integrated Circuit Emphasis) was a very early commercial sim. So many of the free ones use some variant of spice in their name. LTSpice, Qspice, etc.
Kicad is an excellent free schematic capture and simulation software.
Thanks. (And KiCad I am very familiar with already. I love that app.)
I don't think the vibecoding jab is warranted, but I agree this is a pretty terrible UI for electronic circuits. Schematic capture exists for a reason! It's not even difficult for beginners to understand if you have a decent UX (which for some reason seems to elude 90% of PCB software).
Got to agree. This is kind of pointless. Breadboards exist to make it easier to build physical circuits. I would also argue there is paedagogical value in actually playing with a physical breadboard. Having to physically orient things in 3D space is a small price you pay for building a physical prototype. This is all the downsides with none of the upsides.
The upsides are the measurement tools built in.
You have those in all simulations.
Sure. It's an upside to breadboarding in the real world though.
This is so damn cool. I remember 10-12 years ago i used to teach kids to do these things manually. This is a great product for kids to experiment and then run it real life on their kits.
I feel like the fade-in animation when starting/stopping the simulation takes too long. Also, I think it would be helpful if the currently connected row was highlighted when dragging a pin.
I'm working on a similar project, it's called schematik.io and you can use it to generate hardware projects (schematics, components lists, code, everything). Love the 3d viewer they've done here.
Are there similar solutions without 3d view? I want to get a simulator that can show me what is going in the circuit, ideally slowed down a lot. For example I was making a dongle with resistor and capacitor which was delivering a pulse-short (i.e. removing power for a short period of time instead of delivering an impulse) and while I was able to confirm overall idea with some online simulator, dialing in capacitance and resistance required physically switching components. Ideally I want to be able simulate such transient effects and arrive at specific numbers ready to be soldered.
And I want it to be free/open-sourse ideally :)
Sounds like you are looking for a SPICE like simulator, there are quite a few free/open:
https://en.wikipedia.org/wiki/List_of_free_electronics_circu...
orcad is the commercial classic for doing schematics with a spice backend. (spice is an oss engine out of berkeley for simulating circuits on computers. for dc it just solves the classic nodal analysis and for ac you can feed in things from a fantasy signal generator and capture things at various nodes in the circuit) there's also some pretty cool looking commercial web thing now that also will maintain netlists with real-time prices and will let you swap parts out and set minimum quantities etc.
kicad is the oss orcad, but i never got good at it. (to be fair, orcad was weird to learn as well)
I think altium has taken over as the top tier commercial offering in this space.
I always disliked Orcad. Especially because cadence had excellent software that predated OrCAD, and for reasons that I cannot fathom chose to promote OrCAD after they acquired it instead of the better software.
Here's a specific example in the interface. If you wanted to draw a wire, the keyboard shortcut of the old software was 'w' but orcad required you to type 'ctrl + w'. Why are you forcing me to use control when w doesn't do anything on its own? It was filled with similar tiny annoyances that just slowed things down. (Admittedly, it's been years since that was my primary work, and free stuff is good enough for what I do now.) I sincerely hope that orcad has continued to improve over the years.
Altium has taken over a lot of small to medium sized shops. Mostly because the price is right for its capability. It also has a history of being the least bad compromise between the odd mixtures of excellence and user-hostility Cadence and Mentor tend to come up with, going back to the Protel days, and they've done a good job in the last decade+ of marketing it to those shops. Cadence and Siemens nee Mentor (and maybe Zuken? I've never seen Zuken in the wild, but it always makes these lists) have been neglecting the entry level and smaller organizations and aggressively trying to move their customers to their higher tier offerings during that time. But while it's Altium's flagship product, it is not top tier. It is really entry-level for a professional PCB-level design package, like PADS and OrCAD as opposed to Xpedition and Allegro.
Some people like Everycircuit and Falstad for that.
Not foss but tinkercad circuits (https://www.tinkercad.com/circuits) comes to mind.
Ltspice. Ng-spice
Years ago, around 10-12 years back, our Windows XP PC had software similar to this. Dont remember the name. I used to spend hours experimenting with it. haha Nostalgia.
I could not sign up, because "email rate limit exceeded" but i was wondering if it had a feature to probe the voltage at a certain node.
Damn the 3D graphics look great
This would be useful for opensource hardware projects (aimed at beginners) to literally see how things are wired together. I'm still not at the schematic phase myself. But I use MS Paint wiring diagrams.
OMG the wires flex, damn
Give KiCad a try for drawing schematics. It is FOSS.
Yeah that is still on my list to learn eg. designing my own circuit board. My stuff is still basic eg. wiring together an Arduino/RPi to break out sensor boards.
This was done before, years ago, but in 2D. I forget what it was called. It was like an LT Spice clone with better UX.
https://en.wikipedia.org/wiki/Fritzing
That’s it, but I was also thinking about https://www.falstad.com/circuit/circuitjs.html
This was my first thought: this seems like a web + 3d port of Fritzing. Perhaps they even reuse some of the code?
the 3D look is cool but makes it harder to put stuff together
Nice! You can play Electroboom without actually getting shocked. If you do want the real world experience you can get bags full of components on Amazon for pretty cheap
The simulation needs an "Amazon factor" slider, which randomly makes:
* All breadboard wires have some resistance
* Some breadboard wires have very high resistance
* Some breadboard wires have intermittent contact, recalculated every time components are added/removed from the breadboard
* Some fraction of polarized capacitors are backwards
* All capacitors are overrated for voltage and explode at 70-99% of their rating
* Some LEDs smoke at 10% of their rated forward current
* Brightness variation between LEDs that should be identical
* Semiconductors may randomly be another semiconductor in the same class (e.g. a "2n2222" may in fact be any other NPN BJT in the simulation, or the parameters may be entirely random)
* Inductors have 80% variation in core saturation specs, but other parameters are spot-on
* Any component with writable flash (eg USB vid/pid strings) may randomly not actually have writable flash but instead fixed strings and the writes fake success but the values do not change
Better simulators can do parameter sweeps and monte carlo simulations so you can explore tolerance stackup issues. But most of the failure modes you've listed there are just why you shouldn't build your circuits for one on breadboards and for another with dodgy parts sourced outside of distribution channels.
Interesting if there could be automated circuit designs through it
This is really terrific!!!
Super cool. Wonder if we can input the circuit as code.
> Wonder if we can input the circuit as code.
SPICE. You're describing SPICE. :)
As others have mentioned, SPICE is the traditional answer to that question. But SPICE feels more like a macro-assembler for circuits.
One project that comes to mind for high-level programming style circuits-as-code:
https://github.com/atopile/atopile
Show HN: https://news.ycombinator.com/item?id=39263854 More recent HN thread: https://news.ycombinator.com/item?id=44548449
No one realistically speak SVG. Human consciousness isn't a software built on language. Speech center is just a part of a human brain.
There used to be some really good web-based SPICE interpreters but I can't find them now. This was before javascript ate everything, so you would enter the netlist, click a button, and get a GIF or the current at a specified terminal or whatever
Well, SPICE is still around in its zillion forks and dialects…
AIUI the best frontend is kicad, though I never really tried that, I just wrote the text files by hand.
I want an AI that I throw the simulation and it design the PCB and all verification.
ROTFL.
OK the smoke was really funny
Nice, reminds me of https://wokwi.com/ .
Also the amazing https://www.falstad.com/circuit/circuitjs.html
Black screen with "Application error: a client-side exception has occurred (see the browser console for more information)."
lacks exception catching for when webgl is disabled
wow. looks amazing
this is dope
Lol, it simulates magic smoke as well.
Holy requests, batman.
... Why so many requests for a static asset?
Because it's yet another slopware of course
Please don't. The project is around since at least 2022.