Nowadays, the use of data-acquisition systems in undergraduate laboratories is routine. Many computer-assisted experiments became possible with the PASCO scientific data-acquisition system based on the 750 Interface and DataStudio software. A new data-acquisition system developed by PASCO includes the 850 Universal Interface and Capstone software. The new interface is much more powerful than previous ones from PASCO, while the new software provides many additional options for processing experimental data. The two demonstrations described below use the sweep frequency option, which is now available. By specifying the initial and final frequencies and the sweep time, this option makes possible the determination of the frequency response of any frequency-dependent device. The first demonstration shows the electromagnetic screening by metals and can serve as an introduction to studies of the eddy currents and skin effect in conductors. The second demonstration shows the resonance curves of an LCR circuit.