Abstract :
A sinusoidal alternating voltage is generated and applied to the input of an unknown four-terminal network; the output voltage of the network is displayed on the Argand diagram reproduced on the screen o a cathode-ray tube. As the frequency is varied, the circle diagram of the network is traced on the screen and resonances are indicated by loops in the trace. The broad principles are given of an equipment working in the frequency range 5-215 kc/s, which has already been described elsewhere. Full details are given of a second equipment for the frequency range 100 kc/s - 3 Mc/s. Frequency calibration means are discussed. The chief applications of these two designs are described-the assessment of electromechanical transducers, and as bridge detectors in electromechanical measurements of elastic constants. Numerous electrical circuit applications, such as the display of Nyquist diagrams, would also be possible.
