The Wireless Experimenter's Manual; Incorporating How to Conduct a Radio Club

The Wireless Experimenter's Manual; Incorporating How to Conduct a Radio Club

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ...turns of both windings will overlap providing undesirable electrostatic coupling between them. This may prevent sharp resonance at some wave lengths Following Fig. 137 in detail: The secondary inductance is varied by a simple multi-point switch. Some amateurs take off taps every 10 or 15 turns. Resonance between taps is established by the shunt secondary condenser C-l. Fia. 137. Fundamental circuit of the inductively coupled receiving set using a crystal rectifier with a local battery. The diagram shows the relative positions of the '"used" turns of the primary and secondary coils. The plan of Fig. 137 appeals to the amateur who does not care to go to the expense of a "tens" and "units" switch for the primary coils. The number of turns in the aerial tuning inductance is varied by a simple plug contact switch, while the primary has a simple multi-point switch. The primary coil is tapped, at about every 10 turns. Resonance to any wave length occurring between the primary taps may be secured either by shunting the primary with a variable condenser, or by placing a variometer in the antenna circuit. Considerable tuning between taps can be effected by change of coupling between the primary and secondary coils alone. If the detector in Fig. 137, is a carborundum rectifier, the battery B should have an e.m.f. of 4 volts. The potentiometer P is one of 400 ohms. Condenser C-2 may be one of fixed capacity--some value between 0.002 and 0.005 mfd. The telephones should be of 3000 ohms resistance. The beginner should study the practical application of the foregoing inductance and wave length formulae and make several calculations of the possible wave lengths with various coils. This will instill in his mind a relative sense more

Product details

  • Paperback | 100 pages
  • 189 x 246 x 5mm | 195g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236637313
  • 9781236637314