For constructing circuit diagrams in an electronic circuits laboratory class, several free and user-friendly software options are recommended. XCircuit is a straightforward tool for drawing circuit diagrams. Circuit Maker offers a free student version that includes simulation capabilities. Electronics Workbench, while not free, is noted for its ease of use and is available on certain faculty computers. For more advanced simulation, OrCad is suggested, though it is more complex. LTSpice, provided by Linear Technologies, is highlighted as an excellent free tool for schematic capture and simulation, with a supportive user community and helpful tutorials. Overall, these programs cater to different needs, from basic diagramming to advanced circuit simulation.