app.diagrams.net

app.diagrams.net
After creating a new diagram, click on the (More Shapes…) button on the left panel
Find the option for (Other → Electrical) and select it.
Use the left panel to select circuit elements, click & drag elements onto the canvas.
To connect elements, make sure the elements aren’t selected and click on a blue 'x' on the image (it should have a green circle around it when you hover over a connector)
To rotate elements, use the right panel → Arrange
Op-amps and ground are under (Electrical/Misc)

Circuitikz (LaTeX package)

https://www.ctan.org/pkg/circuitikz
Online manual is here: http://texdoc.net/texmf-dist/doc/latex/circuitikz/circuitikzmanual.pdf
Coordinates are (right,down) for (x,y)
Some (downloadable) online examples are here: http://texample.net/tikz/examples/circuitikz/
Not recommended if you aren't writing your reports in LaTeX

https://www.digikey.com/schemeit/
Under the left panel, (Schematic symbols) is where to find the symbols we use in class.
Resistors are under (Passives → Resistors)
Voltage supplies and ground are under (Ports)
Voltmeters/Ammeters are under (Test equipment)

https://www.kicad.org/download/
Free, but requires local installation
To get started:
- Create a New Project
- Edit the schematic (top icon on the left)
- Use the Place Symbols button to select an element
  - You'll very likely need the search function to find things
- Use the Draw Wires button to connect elements
- Use the Place Directive Labels tool to add labels to locations
- Double-click on an element to edit its properties
  - Reference is usually for the name of something
  - Value is usually for physical parameters (resistance, capacitance, etc)
KiCad is capable of simulating circuit behavior, but that is not part of the course.