Implementing a simple vectorial bridge with a digital oscilloscope

Abstract

We show how to exploit instrumentation available in undergraduate student laboratories to build a simple vectorial bridge. In particular we take advantage from the possibility to read data from a digital oscilloscope with a personal computer and describe an algorithm to obtain an accurate evaluation of the phase difference between two sinusoidal signals. The use of the bridge to characterize components of a high Q RLC filter is shown to greatly improve the understanding of results in resonance experiments. Direct evidence of dielectric losses, of skin currents and of the effect of distributed capacitance is obtained.