Experiments Tesla. - When fast electrical oscillations of the magnetic field, of course, I, too, very quickly, so the inductive action of fast oscillations can be extremely powerful, especially if it has to take advantage of the phenomenon of resonance.
This is done in the following location experience Tesla (Fig. 453 a).
Fig. 453 a. Driving experiments Tesla.
Inductor J supplies electricity to the capacitor (7, with the spark gap F and the conductor L is fast electrical oscillations. The conductor L consists of a small number of turns of thick wire. Inside this primary coil L is placed secondary coil ab with great speed, which is why there are very high voltage. If accordingly a large number of turns, i.e. respectively, with greater self-inductance, to make the capacity of the secondary coil is smaller than the first, it is possible to achieve resonance of both systems, causing oscillation of the secondary coil further increase. In this way Tesla reached in the secondary coil spark several meters long.
Fig. 453 b shows the Tesla device that is often used in the demonstrations. Here F -capacity, R - and the primary coil K1 K2 - the poles of the secondary coil, Y - knob for adjusting the spark gap.
Sounding voltaic arc .- Duddel invented a new method of producing electrical oscillations. Driving this process (Fig. 454) is the same as Hertz, but instead of the spark gap used herein voltaic arc, and serves to supply a constant
relatively low voltage current. Voltaic arc, consisting of a free-flowing hot gases, does not represent a constant resistance, resulting in an electric current circuit, and with it the potential difference is constantly changing. Of these:
Fig. 453 b. Device for experiments Tesla.
Change the system LC amplifies, or rather, accumulates in himself those corresponding to the natural period of T = 2 π √ LC.Fluctuations of this period are therefore particularly strong and, in turn, for
Fig. 454. Driving Experience at Duddelya.
Chin influence fluctuations in the arc gas; and periodic oscillations of these gases further reinforce the electrical oscillations in the system LC, and so on. 1 As a result, at the location Duddelya receiving, firstly, the electric oscillation, i.e. an alternating electric current in the LC, and at the same time she makes a sound arc. This sound can be heard if the dimensions of the container and the self-inductance such that the number of vibrations of the system is in the range of distinguishable ear i.e. between 30 and 30,000 cycles per second.
With arc Duddelya very well demonstrated by the formula Kelvin. Thus, while increasing capacity and self-induction period of oscillations increases, and at the same time we hear in the arc, respectively, the lower the sound; Conversely, a decrease in capacity, or the self-inductance is increased, and so the sound, etc. However, for accurate measurements, this method is not suitable, because the resistance of the arc - and it also depends on the period of oscillation, - very unstable.
Fluctuations potentials obtained by the method Duddelya, though not as strong as in the method of Hertz, but they have an almost constant amplitude, i.e. represent undamped oscillations. This last quality is very important at resonance. The less attenuation, the more sharply pronounced resonance.
1 DC, and voltaic arc are here like singing the gas flame so-called "chemical harmonics." There is also a constant current of gas or air by vibrations and resonance is converted to AC, i.e in the sound waves. A similar effect bow on a violin string.
For To power system oscillations LC not branched off in the main chain, and mainly directed to the arc in the main chain of a relatively large set of self-induction.