Well it's a good effort. Why do you need the op-amps? You could just use a voltage divider down to the ADC input directly. Also your op-amps won't work without a negative power supply connection. Finally you need bypass caps on all your ICs (though I assume you left them out).
For circuit simulation, there's always LTSpice. It's "free". No really it's free.
There are a few better schematic capture programs available other than MSPaint as well.
Note that every engineering solution sucks in some way. You usually try to get the one that's the least suckiest. However, sometimes a solution is so slick it's like a work of art. That's nirvana.
Answering to myself (in case someone else is interested): It seems that LTSpice can do this - at least it can export WAV files of the waveform at some point in the circuit.
However, I'm still interested in finding a simulator that could do this live, so I could hear the result immediately. I found LiveSpice, but it seems experimental and hasn't been updated since 2014.
Apart from the other relevent suggestions offered by other posters here, download LTspice, a free program to simluate electronic circuits. You can find many examples of LTspice circuits for FX pedals via google and the Yahoo LTspice group, and many tutorials via google/youtube as well.
There are many online places offering PCB boards and/or FX pedal kits, including everything you need to assemble a pedal (PC, components, and build guides).
I'm gonna be a dickhead and say that ltspice exists for a reason.
The same dickhead would punch it into ltspice if he could read the values so you know what to do.
You could run the Windows version of LTspice through Wine:
sudo apt-get install wine
Even if your going entirely analogue you're going to need to know how to do at least some coding to stay competitive. That said I would recommended doing two things:
1)Playing around with an arduino. Its $30 that will give you a jump start with embedded projects. If you decide your ready for more complex embedded projects it can also act as programmer for bare AVRs (a simple ISP programmer will probably cost you around $20). Its also good for prototyping/debugging circuits.
2) The second thing is getting familiar with SPICE. Generally I've found that for complex circuits you do some back of the envelope calculations then put it into SPICE to get closer to the operating points your looking for. Try LTSpice its free and has a nice graphical editor so you don't have to draw out all the nodes by hand like you would with a purely text based SPICE program. SPICE will also help you check your answers for homework problems and stuff.
You probably don't need a book. You need hours and hours of experimenting on a simulator to understand concepts.
LTspice is free, and provides you the means to simulate a variety of circuits. If LTSpice is "too complex", there are some simpler tools to use. But LTSpice is at a good point of very cheap (aka, its free) and relatively accurate.
Real lab work is still necessary, but if you're still in the "conceptual" phase, simulations are sufficient for beginners. Once you get a bit of intuition, then you start working with real-life flawed components (ex: +/- 10% tolerances and whatnot).
LT spice XVII is a nice version of SPICE that is free. Also, it gives you access to the entire Linear Technologies library of parts as well as example schematics for those parts. Here is a pretty good tutorial: http://www.simonbramble.co.uk/lt_spice/ltspice_lt_spice.htm
Sorry, but for this type of problem we really need a schematic to efficiently help and debug.
If I click on the schematic view on your link, I get a mess of wires and it appears that the power supply isn't connected at all and all the LED cathodes are floating too.
I have no idea how good the 123D circuits simulator is. LTspice is widely used in the industry and free too, although it's probably a bit harder to use at first.
Funny coincidence: I study electrical engineering :D. Well, there are free circuit simulators out there, namely LTspice. But working with it doesn't really feel like a game...
I saw your post last week but I'm still a bit confused as to what this project does. Is it simply a breadboard layout tool similar to Fritzing that does breadboard and pcb layouts or is it something similar to LTSpice/Circuitmaker or a combination of the two?
Use LTspice. It's a powerful, free SPICE simulator and there are tons of tutorials on how to use it available on the web. In LTspice there is a NE555 model available, too. A quick glance through your comment history tells me that you are German, so this website might be of interest:
www.gunthard-kraus.de/LTSwitcherCAD/index_LTSwitcherCAD.html
Also check out Dave Jones' EEVblog youtube channel if you want to get into electronics.
LTSpice was definitely my favorite circuit layout program during undergrad. It's so simple, powerful, and free. Here's the download link for the curious: http://www.linear.com/designtools/software/#LTspice
I recommend a good SPICE simulator to everyone.
Not just to prove and test your ideas, but, even more importantly, to communicate your circuits to others when seeking help when you have done everything perfectly, and the damb thing still won't work.
This is a good one, generously provided for free by Linear Technology: LTSpice.
Good luck.
I would recommend the redesign done by hj01bg but would encourage you to understand why your design did not work. Check out this software, it lets you play around with your circuit design in a neat way, might be helpful. LTspice IV http://www.linear.com/designtools/software/#LTspice
>Just a couple questions about output characteristic curves: where can you find them?
Honestly, I'm not sure. I rarely see I-V curves on datasheets. When I was in school we'd sometimes construct them in excel by doing measurements, or use a SPICE porgram to generate them based on the transistor model, but I've never actually encountered transistor I-V curves used in the real world. It's not necessarily that they aren't used, I just don't know.
>Are they unique to each transistor
Yes, they are unique to the transistor. Most BJTs will have very similar looking I-V curves, but there will be small differences depending on the device. Even two transistors with the same part number will have slightly different I-V curves.
One more thing: if you plan on doing analog circuit design work like this, I highly recommend learning how to use a SPICE simulator for prototyping. It's a lot faster than breadboarding. Once you learn the basics, you can quickly make changes to the circuit and see the results almost instantly. Most people these days (at least outside the oddball pedal world) do the initial prototyping in simulators first before they breadboard.
Check out LTspice. It's awesome, easy to use, and free! You can toy with transistor amplifiers all you want and really push things to the extreme without worrying about breaking anything. You can even go into the component models and edit parameters to see how it affects their operation. It's a great learning tool. The LTspice yahoo group has tons of SPICE models for different components that you can download and use in the simulator.
Yeah the voltage at B is the capacitor voltage (B to ground is across cap). I believe the capacitor is staircasing up because of a clamping. Clamping happens when you have diodes and capacitors in switching circuits. The capacitor retains its voltage while the diode is off, and resumes charging up when the diode is on. It eventually saturates to a higher voltage. It's used a lot and is a kind of voltage-multiplier.
Removing the resistor, doesn't seem to do much. The inductor also seems to be uninteresting...
I would download Lt spice and play around. It's free, and easy to pick up. http://www.linear.com/designtools/software/#LTspice
Hmm, maybe a problem from using the 22uH?
I set up a similar LT driver (LT1937) and used LTSpice to play around with all the values. It gives a pretty clear picture of what's going on.
As an electrical engineer myself, I think the best way to get started with hardware is to start tinkering. Get an Arduino and start playing with it. Get used to working with transistors, diodes, power supplies etc. If you don't already know SPICE, I would recommend learning it, a great tool that's free is LTspice: http://www.linear.com/designtools/software/#LTspice
Just play around with LTspice, design a few simple switching power supplies with it. Naturally use the datasheet for a part to help you with that.
Last but not least, learn how to design your own PCBs! I've met too many electrical engineers that don't know the first thing about PCB design. Get EAGLE and start here: http://www.sparkfun.com/tutorials/108
Make a cool circuit, blink a few LEDs, make a headphone amp, make an LED cube, just start making something! Get your PCBs manufactured, order the bill of materials, build your project; and repeat.