learning resources teaching telephone

Two-way operation is essential for satisfactory telephone service, and many of the problems of the industry arise from this fac..

Telephone Circuits - Two-way operation is essential for satisfactory telephone service, and many of the problems of the industry arise from this fact. A simplified circuit for obtaining two-way operation is shown in the below figure. This is called a local-battery system because..

Telephone Lines - The transmission lines used in telephony are of two kinds: open- wire and cable. The open-wire lines are gradually being superseded by cable construction, either overhead or underground, for two principal reasons. In the first place, many more circuits can be accommodate..

Microphones - A microphone is a device that transforms sound pressure into electrical energy. In most types of microphone, the sound pressure acts upon a thin plate or diaphragm, setting it into vibration, and this mechanical motion is then utilised to produce electrical effects. The chief types ar..

The transmission lines used in telephony are of two kinds: open- wire and cable. The open-wire lines are gradually being superseded by cable construction, either overhead or underground, for two principal reason..

Edaphic Resources (Soil Resources) - Edaphic resources refer to soil resources. Due to varying temperature, rainfall, topographical characters in different parts of world, the rocks weather differently. Further, the rocks themselves are of varying chemical co..

The smallest conductor used in standard open-wire telephone circuits is No. 12B and S. gauge. A line of such construction will have a loss of approximately 0.06 db per mile. Cable circuits, on the other hand, make use of conductors not larger than No. 19, and a typical cable circuit with ..

The living resources include the plants, animals and the microbes. They are also called the organic resources..

Microbial resource is a resource not seen by naked eyes, like all other resource. But it is a powerful resource existing in all parts of globe - in atmosphere, on the earth, inside the earth, on the sea and inside sea, inside the bodies of animals and p..

These are shared by all nations. Examples: Air and solar energy. Study of natural resources can be treated to have run parallel to course of human development as well as parallel to the course of evolution of science itself. The study of natural resources has been an inseparabl..