The applications given below fall into two categories. In some of them, the QuadTech 1689 fills a definite need and can make better measurements than any available manual bridge. In others, the 1689 can make the required measurements, but not as well as specialized, expensive lab instruments. This latter category extends to all ac impedance measurements at or below 100 kHz, so for many standards labs that don't require the highest accuracy, the 1689 becomes a "standards lab in a box."