The thermionic vacuum tube and its applications (1920)
Van der Bijl, Hendrik Johannes, 1887- · New York McGraw-Hill Book, Co · leaf 239
circuit arrangement used for testing audio frequencyamplifiers is shown in Fig. 111. f/ is a source of alternatingcurrent which will be described later. The current is prefeiablypassed through a wave filter to obtain a pure note of about 800cycles per second. By means of the switch W this current…
Telegraph, Wireless
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
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