The University of Canterbury recently developed a biochip, or “lab-on-a-chip” platform, which is used for the diagnosis and fast analysis of biological samples [1]. The biochip uses dielectrophoresis (DEP) to manipulate cells and other small particles [2]; this requires a.c. waveforms with well-defined frequency and amplitude. Hence, a dual-channel signal generator, capable of generating sine, square and triangle waveforms at frequencies up to 20 MHz and amplitudes up to 20 Vpp, was designed and built. A series of experiments using the signal generator and biochip demonstrated the effects of positive and negative DEP on polystyrene beads.