Performance-Based Assessments for Digital Circuit Competencies

Students are to research the datasheet for their particular IC and figure out from that what connections and timing sequences they need to make the circuit perform as requested. It is very important for students to learn to interpret manufacturers’ datasheets!

I recommend a slow clock frequency (1 Hz or so) to allow for easy viewing of the shift patterns. To conserve the number of necessary input switches, I allow students to hard-wire the data inputs (D₀ through D₃). This means they only need switches to control the mode of the shift register (parallel load, shift right, shift left, and shift inhibit).

Use a four-pole, unipolar stepper motor for this assessment, with a power supply capable of sourcing the required current.

An extension of this exercise is to incorporate troubleshooting questions. Whether using this exercise as a performance assessment or simply as a concept-building lab, you might want to follow up your students’ results by asking them to predict the consequences of certain circuit faults.

An extension of this exercise is to incorporate troubleshooting questions. Whether using this exercise as a performance assessment or simply as a concept-building lab, you might want to follow up your students’ results by asking them to predict the consequences of certain circuit faults.