Experiment with Arduino: Charging and discharging of capacitor, RC with potentiometer
Experiment with Arduino: Capacitive touch, digital voltage input levels $V_\mathrm{I,H}$ and $V_\mathrm{I,L}$
Experiment with PicoScope: RC lowpass with signal generator
Simulation with: LTspice simulation of RC lowpass, parametric sweep
Bode plot
Complex numbers