Pertains to electronic wide-band transformers transmitting power within a wide band of frequencies covering typically at least one decade in the frequency spectrum. Provision is made for including data for use in the design of feedback amplifiers and control networks or other circuits in which the knowledge of the transformer amplitude and phase-frequency response is needed by the system designer. These transformers are required to transform voltage within specified tolerances of amplitude and phase when operating between specified impedances. Guides to the application and test procedures are included. These appendixes contain certain precautions and recommended practices. The standard also pertains to hybrid transformers, primarily used in the telecommunications industry. The hybrid transformer is a wide-band transformer used in a manner which makes it part of a capacitance, resistance and/or inductance network and it must have characteristics which permit it to match the network for proper overall performance.