Various Tesla book cover images

Nikola Tesla Books

Books written by or about Nikola Tesla

Nikola Tesla: Colorado Springs Notes, 1899-1900 Page 189

September 17-18, 1899

investigation outside and such use. The synchronized coil was wound in one instance around a drum 10" in diam. and about 4 feet high from the ground and carrying on top a board for placing the box with the instruments and supporting a light rod for air or capacity wire. In another form of apparatus the synchronized coil was wound on drum of 2 foot diam. and 18" high, which was supported on a tripod of photographic outfit.

These two connections illustrated in Diagrams 1. and 2. were found best suitable. The small condenser around secondary s comprised only a few sheets of mica a sufficient to let the currents of a frequency of 50,000 per sec. pass through easy.

Colorado Springs

Sept. 18, 1899

Experiments were resumed with all transformers in place, high speed break and connection in multiple arc of West. Transformer, The object was to further test the intensity of the vibrations produced particularly without spark. The connection was as in diagram. It was though that in this arrangement, which was dwelt upon before, the disturbances were produced more economically than when using a spark discharge. The experiments fully confirm this.

In the tests the capacity of the two balls of 18" diam. did not very materially derange the adjustment and period of the circuit. This is to be expected; as for the secondary the capacity was far too small and on the other hand the independent vibration of the extra coil could not be materially interfered with since the condenser formed by the two balls and zinc plate allowed free passage of currents to earth. Now the important thing was to decide whether it is better to make length of extra coil one half or one quarter of wave as before. This to be thoroughly investigated. The working was excellent with 1/4 wave length.

189

Source:
by Professor Aleksandar Marinčić

September 18-19

As already remarked, oscillators like those he was working with here are not the classical Tesla oscillator with a resonant transformer. The “extra coil” essentially changes the loading of the secondary circuit, and this alters the mode of oscillation. Also, shunting the secondary with capacitance (as in the diagrams of 18 September and 19 September Figs. 2, 3 and 4) alters the spectrum of the oscillation in comparison with that yielded by an oscillator with two oscillatory circuits. Configurations such as those shown in Figs. 5 and 6 of September 19th can be considered as typical Tesla oscillators with a loosely coupled third circuit consisting of the extra coil and capacitive load. Then the greatest voltage at the free terminal of the extra coil is obtained when the natural resonant frequency of this circuit (together with the ball antenna) is the same as that of the strongest component in the spectrum of the oscillator.

Source:
by Professor Aleksandar Marinčić

September 18-19

As we mentioned previously, oscillators such as these with which he now experiments do not belong to the classic Tesla oscillators since resonant transformer "additional" coil substantially changes the secondary circuit loading and that will change the manner of oscillation as well. Also, the additional capacitance (as shown on schematics of Sept. 18 and 19 in Figs. 2, 3 and 4) in parallel with the secondary, will change the oscillation spectrum in relation to that which is produced with an oscillator with two oscillating circuits. The connections as on Fig. 5 and 6, given on Sept. 19, could be considered as typical Tesla oscillators with a weak-linked third circuit, which consists of additional coil with capacitive loading.

In that case, he achieved the maximum voltage at the "additional coil" terminals when the natural frequency of this circuit (together with the aerial globe) is equal to the frequency of the strongest component in the oscillator spectrum.

Contents

Introduction
June 1 - 30
July 1 - 31
August 1 - 31
September 1 - 30
October 1 - 31
November 1 - 30
December 1 - 31
January 1 - 7
Commentaries

Appendices: I, II

Images

Glossary

Lowercase tau - an irrational constant defined as the ratio of the circumference of a circle to its radius, equal to the radian measure of a full turn; approximately 6.283185307 (equal to 2π, or twice the value of π).
A natural rubber material obtained from Palaquium trees, native to South-east Asia. Gutta-percha made possible practical submarine telegraph cables because it was both waterproof and resistant to seawater as well as being thermoplastic. Gutta-percha's use as an electrical insulator was first suggested by Michael Faraday.
The Habirshaw Electric Cable Company, founded in 1886 by William M. Habirshaw in New York City, New York.
The Brown & Sharpe (B & S) Gauge, also known as the American Wire Gauge (AWG), is the American standard for making/ordering metal sheet and wire sizes.
A traditional general-purpose dry cell battery. Invented by the French engineer Georges Leclanché in 1866.
Refers to Manitou Springs, a small town just six miles west of Colorado Springs, and during Tesla's time there, producer of world-renown bottled water from its natural springs.
A French mineral water bottler.
Lowercase delta letter - used to denote: A change in the value of a variable in calculus. A functional derivative in functional calculus. An auxiliary function in calculus, used to rigorously define the limit or continuity of a given function.
America's oldest existing independent manufacturer of wire and cable, founded in 1878.
Lowercase lambda letter which, in physics and engineering, normally represents wavelength.
The lowercase omega letter, which represents angular velocity in physics.