Various Tesla book cover images

Nikola Tesla Books

Books written by or about Nikola Tesla

Nikola Tesla: Colorado Springs Notes, 1899-1900 Page 401

June 16

through the Earth. He had already put forward the hypothesis that the Earth could be used as one of the conductors in transmission of energy from a transmitting to a receiving aerial in 1893(6). He further developed this hypothesis in his patent application “Apparatus for transmission of electrical energy” filed in 1897(13).

June 18

The secondary circuit was modified by the addition of another coil, altering its response to the primary and the spectrum of the oscillations. Tesla had already found in experiments in New York that this “extra coil” had a good effect. This coil was not inductively coupled to the transformer (some coupling probably existed, though weak).

June 19

Continuing his study of the receiver components referred to between 9th and 11th June, Tesla describes a sensitive detector using the attractive force between the plates of a charged condenser. Descriptions of allied devices are to be found in several of Tesla's patents. In patents(8) and (9) this effect is used to periodically make the receiver circuit when main condenser charges up sufficiently (there is no preexcitation nor quenching, since the circuit quenches itself when all the stored energy gets discharged). A fuller description, where it is noted that the performance of the device is improved under reduced air pressure, may be found in patents(70).

June 20

Tesla did not make a strict theoretical analysis of the mode of operation of his oscillator, but determined all the main parameters by tests on a simplified representation of the oscillator circuit. For example, he estimated the power supply drain from the energy in the primary circuit capacity multiplied by the rate of discharge. This involves the assumption that the condenser charges up by the same amount before each discharge (which cannot be the case when it is charged from an AC supply) and that all the energy gets dissipated before the next charging.

The “vibration”, i.e. the resonant frequency of the primary circuit is calculated from the measured inductivity of the primary with two turns (see June 17th) and its capacity. Since he was now using one turn, the inductance is divided by 4. The capacitance was somewhat greater than that measured on June 18th with the old jars. Using these L and C values he calculates the resonance period of the primary using Thomson’s formula for a lossless circuit.

He then finds the wavelength of the primary oscillations, and hence works out the number of turns the secondary must have so that its length is one quarter of a wavelength (see the commentary to 7th June). It is not surprising that he went astray in trying to set up a representation of the secondary circuit as an oscillatory system since the distributed

without wires(6) where the alternating current source is connected “with one of its terminals to earth (conveniently to the water mains) and with the other to a body of large surface P''. Popov's receiver of 1895 also used rounding via a water pipe(32). Around 1895 Marconi did some experiments with a Hertz apparatus grounding one terminal of the inductor and leaving the other connected to an elevated conductor with a terminal capacity. Exhaustive studies of the influence of the form of grounding and the nature of the ground were made around 1905 and later(30).

26

401

26

Tesla: “Electrical transformer”, U.S. Patent, 593 138, Nov. 2, 1897, Appl. March 20, 1897, P-252

30

Fleming: p. 792.

32

Попов А.С. "Прибор для обнаружения и регистрирования электрических колебаний”, Журн. русского физ.-хемич. о б-ва, 1896, t. 22, 4. физич., отд. 1, вып. 1.

English: Popov A.S. "A device for detecting and recording electrical oscillations", Journal of the Russian Physical and Chemical Society, 1896, vol. 22, 4. physics, sect.

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.