Soundcard Oscilloscope by Christian Zeitnitz

The Soundcard Oscilloscope receives its data from the Soundcard with 44.1kHz and 16 Bit resolution. The data source can be selected in the Windows mixer (Microphone, Line-In or Wave). The frequency range depends on the sound card, but 20-20000Hz should be possible with all modern cards.

Soundcard Oscilloscope by Christian Zeitnitz

The oscilloscope contains in addition a signal generator for 2 channels for Sine, Square, Triangular and Sawtooth wave forms in the
frequency range from 0 to 20kHz. These signals are available at the speaker output of the sound card. These can be fed back to the
oscillocope in order to generate Lissajous figures in the x-y mode.

These is another good tool for students to learn measurement on the PC.  – delabs