Articoli correlati a Electricity, Its History and Development
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 edition. Excerpt: ...different frequencies of vibration are mounted over the cores. With the springs at rest a steady current which may be indicated by the uniform height of the straight line marked " at rest," in the lower part of the figure, flows through the circuit. If now one of the springs over the sending magnet is " plucked" and thus thrown into vibration as it approaches the magnet core more magnetic lines pass through the magnetic circuit; while as it recedes from the core the number of magnetic lines decreases; and this movement of lines of force across the winding of the magnet causes an alternating e. m. f. to be generated in the coil which periodically aids and opposes the e. m. f. of the battery in the circuit. As a result the current through both the sending and receiving magnets is now represented by the height of the wavy line in the lower figure--which simply means that the current varies with the passage of time as the height of the wavy line varies when we pass from left to right of the figure. In other words, the receiving magnet is strengthened and weakened as many times per second as the sending spring vibrates, and in consequence that receiving spring which has the same natural frequency--or would vibrate the same number of times per second if plucked--is thrown into violent vibration. Bell's training in acoustics enabled him at once to appreciate that this method of transmitting vibrations might be so modified as to succeed where the make and break method failed--that is, in the transmission of "quality" of sound. For quality depends not on the frequency of the vibrations constituting the main tone but upon the lesser vibrations of higher frequencies superimposed upon this tone, so that while two voices...
Le informazioni nella sezione "Riassunto" possono far riferimento a edizioni diverse di questo titolo.
- EditoreTheClassics.us
- Data di pubblicazione2013
- ISBN 10 1230428135
- ISBN 13 9781230428130
- RilegaturaCopertina flessibile
- Numero di pagine36
(nessuna copia disponibile)
Cerca: Inserisci un desiderataSe non trovi il libro che cerchi su AbeBooks possiamo cercarlo per te automaticamente ad ogni aggiornamento del nostro sito. Se il libro è ancora reperibile da qualche parte, lo troveremo!
Inserisci un desiderata