[NS86ADC2], Technical Note, Thomas Alva Edison, John F Ott, March 18th, 1886


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[NS86ADC2], Technical Note, Thomas Alva Edison, John F Ott, March 18th, 1886

Editor's Notes

written from Fort Myers: "John Tate says the operators on Phonpl buckle the diaphragm, that they cannot tell when the magnet is the right distance or even when it is touching the diap'm they keep on turning until the diaphragm is badly buckled. please try some experiments to stop this. I make one or two suggestions thus (drawings) A is a lever which has a handle outside of telephone case B is an end on it of brass & fits down in a slot in the iron magnet it is flush with the top. When the magnet is say 1/32 from face of the diaphragm you work the lever from the outside up and down & this tells you how far it is away Of course when the diaphragm touches the face of the magnet you cant work the lever at all-- This lever serves to tell you just where you are & the distance-- perhaps a single lever & piece will answer (drawing) Another way is to make the diaphragm one pole & the head of the magnet the other pole or contact point & when the magnet touches the diaphragm it closes the circuit around the sending key that works the sounder (drawing) The operator can leave his key open & adjust until it closes the sounder and then he knows that the diaphragm and magnet are in contact-- I dont think this as good as the lever Another way is an index lever (drawing) This I dont think so good as the lever as the diaphragm may get buckled & then the index wouldnt show proper (drawing "Made and test this April 12 86 J. F. Ott") Here is an experiment I want you to try & see if it wont work fartehr or louder than the others X is a one or 2 ohm Bell Receiver magnet, G is the regular weight secured to lever N. a local battery is used which is broken when the weight leaves the diaphragm This tends to make a self vibrator but I want it so adjusted and the weight so heavy that it wont act as a self vibrator, the weight being too heavy or the magnet adjusted so far away or the current being too week by putting in Resistance in the local circuit. Now when the wave comes over the [main?] line it throws the weight up as the Local magnet almost does it the weak line current added to it is sufficient to throw it up. but it now falls back with the full power of the weight as the Local magnet is open thus you get a loud sound due to the falling of a big weight, which without the local magnet the weak current on the main line would be unable to lift"





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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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