Building Circuits in Lab
- We'll be building lots of circuits on breadboards, and it's important to understand how they work and how to use them. Some good descriptions of breadboards and how to use them to build circuits:
- Fritzing is free software that aids in the design of electronic circuits. Among many other features, it has a tool for laying out circuits on a breadboard, letting you work out a good layout for a design before wiring it up in the lab.
Drawing Circuits
There are several programs focused on schematic capture (drawing circuit diagrams) directly. These will do handy things like maintaining wire connections between parts as you move them. A few good free options are:
- Logisim — Installed in the CNS labs, this is a great tool for simulating, testing, and understanding digital logic circuits in addition to its fairly good schematic capture. Use the "File > Export Image..." function to get an image you can use in your lab report. Crop the image to only include the circuit in your lab report and avoid wasting space. Note that Logisim does not have proper circuit diagram elements for LEDs or resistors, making it poorly suited to drawing circuits with those components. [In this course, those elements are needed in the report for Lab 1 only, and no others.]
- SchemeIt — An online schematic editor provided by DigiKey, an online parts retailer. I haven't used it myself, but a student found it useful. It may try to sell you parts (as that is DigiKey's primary line of business).
- CircuitLab — Another online schematic editor. It is a commercial product with a free demo and a subscription fee, but students have reported they can upgrade to the "Student Edition" (allowing saving schematics, etc.) for free with a .edu email address.
- TinyCAD — Use "File > Export as image file..." to get an image for your lab report. Again, please crop the image to avoid wasting space.
- Fritzing — As mentioned above, this could be quite useful for planning breadboard layouts of your circuits before building them. It has a circuit schematic mode that can produce clean circuit schematics (with simple image export functionality) as well.
Logisim is probably the best option of these for all but Lab 1, but feel free to try out the others as well.
Side note: In general, if you want to draw diagrams of any sort with the highest quality and the most control, I recommend using a vector graphics editor (such as Inkscape, which is free, open-source, cross-platform and excellent) as opposed to a raster editor (like MS Paint or Adobe Photoshop). Vector graphics will let you copy, move, and generally edit your drawing with far more flexibility than a raster graphics program can.
Concepts & Terms
- The Binary Number System — a very quick explanation of how binary numbers work, including fractions. There's a slightly longer explanation from a different perspective here.
- And if you don't yet have common powers of two memorized, you'll want to work on that. Knowing at least 28, 216, and 232 off the top of your head will be very useful.
- The textbook's glossary may be useful for quickly looking up technical terms.