An Amplifier to Adapt the Oscillograph to Low-Current Investigations

There has been need in several fields of electrical engineering research for a means to study time relations, wave forms, and similar phenomena where only infinitesimal currents are obtainable. The limitations and advantages of several possible methods of investigation are briefly compared, and the conclusion reached that the ordinary oscillograph can be most profitably adapted to such work. The best form of vacuum tube amplifier for the work is then discussed, followed by a description of the steps taken in the design of a suitable resistance coupled amplifier. This amplifier is then described. The results of tests showing quality of reproduction are given in the form of oscillograms and a characteristic curve. The recommended procedure to be followed and the necessary precautions to be observed in the use of the amplifier are given, with a short discussion of the abilities and possibilities of the oscillograph in its widened field of usefulness.