There are bridges, such as the QuadTech 1615 mentioned earlier that measure capacitance from 1 μF or less with better precision and accuracy than the 1689. The 1689 is not necessarily recommended for inter comparisons of reference standards in high‑level labs, it is however, very adequate for calibrating the reference standards of lower‑level labs and all working standards and decade boxes.

Generally, the 1689 is more sensitive than the 1615 for capacitance of 1 μF or higher at low frequencies. The 1689 applies more voltage and has much better repeatability if many measurements are averaged over the time it would take to balance the 1615. Further, the 1689 is four‑terminal and the 1615 is not, so there are connection errors, particularly those due to series inductance at higher frequencies. The repeatability of measuring a 1000 pF capacitor with the 1689 at 1 kHz is good. The standard deviation should be about  where N is the number of measurements averaged, so comparisons can be very good. The accuracy is less at lower values, so lower values should be compared at a higher frequency. At 10 kHz one can compare a 100 pF standard to better than 1 ppm or a 10 pF standard to better than 10 ppm.

It is interesting to note that the repeatability of the 1689 is comparable to that of the precision 1615 if measurements are made at the same level (1V rms.) and if averaging is used to make the overall measurement time the same. An automatic instrument is not necessarily less precise than a manual one. They both use the same laws of physics and the automatic instrument has the advantage of statistical data manipulation.