The standard method of determining the presence of small currents and their null points has been by the use of the galvanometer. This method has its advantages, namely; one can get some idea of the size of the current by noting the magnitude of deflection, and noise and quality of eyesight have no material effect on the accuracy obtainable. However, in spite of these apparent advantages, the ultimate accuracy of this method is limited principally by the sensitivity of the galvanometer. If a very sensitive galvanometer is used it is delicate and not very rigid nor serviceable. Furthermore the deflections must be rather closely observed thereby making it impossible to use the eye to observe other matters in connection with the test. Below are briefly described a number of methods in which the ear is employed in place of the eye, thereby relieving the eye for observation of other matters. The use of the vacuum tube amplifier also makes possible greater accuracy in fixing the null point. The writer has tried these methods mainly in connection with the regular hydrogen ion titration apparatus where an ordinary galvanometer is usually employed.
Proceedings of the Iowa Academy of Science
©1924 Iowa Academy of Science, Inc.
"Notes on Audio Methods of Determining Null Points in Chemical Tests,"
Proceedings of the Iowa Academy of Science, 31(1), 327-329.
Available at: https://scholarworks.uni.edu/pias/vol31/iss1/92