Compact telephone line transformer - in which use of sintered ferrite core simplifies design to handle ringing, speech and DC signals

摘要

A line transformer for telephone systems, in the form of an autotransformer with two tapped coils separated by a capacitor, and with a core having an air-gap to carry ringing signals, speech signals, and D.C. signals. To simplify the design of the transformer, broaden tolerances, and produce a more compact instrument, the core is made of a sintered material, such as a soft ferrite, which may be designed as a pot core.