United States or Tuvalu ? Vote for the TOP Country of the Week !
An oscillation circuit, as pointed out before, is one in which high frequency currents surge or oscillate. Now the number of times a high frequency current will surge forth and back in a circuit depends upon three factors of the latter and these are called the constants of the circuit, namely: its capacitance, its inductance and its resistance. What Capacitance Is.
The two chief features as far as the parts are concerned of this long wave length receiving set are the variable condensers, and the tuning inductance coils. The variable condenser used in series with the aerial wire system has 26 plates and is equal to a capacitance of .0008 mfd. which is the normal aerial capacitance.
But if you vary the inductance of the one loop so that it is larger or smaller than that of the other loop no spark will take place in the second circuit.
This adjustment is made in the inductance coil because although both the Leyden jar where the spark is generated that causes the oscillations and the antenna can be regulated independently of each other a few turns of the inductance coil affects each circuit. After the two circuits have been adjusted to the same frequency they are said to synchronize.
The Oscillation Transformer. With an oscillation transformer you can tune much more sharply than with a single inductance coil tuner. The primary coil is formed of 6 turns of copper strip, or No. 9 copper wire, and the secondary is formed of 9 turns of strip, or wire. The primary coil, which is the outside coil, is hinged to the base and can be raised or lowered like the lid of a box.
Where high frequency currents surge in a circuit the inductance of it becomes a powerful factor. The practical unit of inductance is the henry and it is represented by the symbol L. What Resistance Is.
They have a capacitance of 1 mfd. and will stand 750 volts. These condensers cost about $2.00 each. The Filter Reactance Coil. It consists of a coil of wire wound on a soft iron core and has a large inductance, hence the capacitance of the filter condensers are proportionately smaller than where a small inductance is used which has been the general practice.
A sort of metal helmet with two receivers attached to it, one on each side, lay handy at Jack's hand. In front of him was the transmitter joined to the metal box which contained the microphone, transformers and inductance tuning coil.
With a loose coupler, as this kind of a tuning coil is called for short, very selective tuning is possible, which means that you can tune in a station very sharply, and it will receive any wave lengths according to size of coils. The primary coil is wound on a fixed cylinder and its inductance is varied by means of a sliding contact like the double slide tuning coil described above.
Inductance coils for short wave lengths are usually wound in single layers but bank-wound coils, as they are called are necessary to get compactness where long wave lengths are to be received. By winding inductance coils with two or more layers the highest inductance values can be obtained with the least resistance.
Word Of The Day