OCR Text |
Show How Taps on Coils Will Aid in Tuning Tapped connections to coils are made to provide a step-by-s:ep variation vari-ation in tlie number of turns. The more common use of the tapped switch is in connection with the primary, where the aerial is made more responsive respon-sive to a high or low wave by the position posi-tion of tlie switch. - ' ' In the aerial circuit the svitch controls con-trols the primary coil by terminals connecting con-necting from every fifth turn of the coil to a tap or metal button, the aerial connecting to the switch arm and the ground to one end of the coil. Uegarding the aerial ami ground as the plates of a tixed condenser of a capacity equal to that of a trrid con denser, or .0002.". microfarads, which it actually is, it is seen that it is necessary neces-sary to add a certain number of turns to the coil to make it tune to a given wave length. Tuning in the secondary is accomplished accom-plished by a tixed coil and a variable condenser, and In the primary coil Inductance. In-ductance. TlTe result Is practically tlie same if one or the other is varied, but beta may not be fixed to obtain efficiency. effi-ciency. The tixed primary is a compromise compro-mise to simplicity. |