This is a degree of sensitiveness that cannot be obtained with any of the astatic instruments known up to the present.
Were the line that joins the two poles vertical, the system would be perfectly astatic in a uniform field, since each magnet in particular would then be perfectly astatic.
But in astatic instruments it is better to place the magnets in such a way that the two branches shall be in the same vertical plane.
The effect of external fields is eliminated by the astatic arrangement of the fields and the moving parts.
Does the astatic galvanometer give correct readings for different values of the current?
In the astatic galvanometer, the earth's magnetism is neutralized by means of astatic needles.
It may be made with high enough period and sensibility to be satisfactory as a ballistic instrument, but for extreme sensibility an instrument of the astatic type is more generally used.
Thompson astatic instruments can be provided with polarity indicators, a red disc showing on the scale card where the poles are reversed.
Explain the construction and principle of the Thompson astatic instruments.
Two small pieces of magnetic metal are rigidly mounted on the shaft and the astatic components of the magnetic field, which are perpendicular to the shaft, tend to keep the pieces of magnetic metal in their initial positions.
He employed for this purpose an astatic circuit B, consisting of a wire bent into a double rectangle round which a current flowed first in one and then in the opposite direction (fig.
It was found to affect a delicately suspended pair of astatic magnetic needles hung in proximity to the disk just as would, by Oersted's rule, a circular electric current coincident with the periphery of the disk.
The astatic circuit was pivoted by suspending it in mercury cups q, p, one of which was in electrical connexion with the tubular support A, and the other with a strong insulated wire passing up it.
A spot of light reflected from a small mirror attached to the astatic system, thus gives the highly magnified movement of the rate of growth, which may easily be raised to ten million times.
In this method a very delicate astatic system of magnets undergoes deflection by the movement of a magnetised lever in its neighbourhood.
An astatic galvanometer is that in connection with which an astatic needle is employed, by the use of which the sensitiveness of a galvanometer is greatly increased.
The deflection of the needles D and C is observed by means of a pointer or glass needle A, B, rigidly connected with the astatic system by a prolongation of the brass rod connecting the needles D and C.
An astatic needle is a combination of magnetised needles with their poles turned opposite ways.
The galvanometer has an astatic needle, suspended by a cocoon fibre, and a flat bobbin frame wound with fine wire.
The uses of the astatic galvanoscope will be studied more fully in later experiments.
The heat of a match, or the cold of a piece of ice, will produce a current even at some distance, the thermopile being connected with a sensitive short-coil astatic galvanometer.
Both of these things are accomplished by using an astatic needle in connection with a coil containing considerable wire.
Connect H with the astatic galvanoscope, A G, as in Fig.
The astatic galvanoscope is not needed; in place of it provide a short piece of metal, such as a battery-plate, or even a jack-knife.
The home-made thermopile described in §421; astatic galvanoscope; connecting wires; candle or alcohol lamp.
Note in which direction the right-hand end of the astatic needle is deflected.
To study the construction and use of a simple astatic galvanoscope.
To study the construction and use of a simple astatic needle.
In case G V is not delicate enough to show clearly which way the current passes, use the astatic galvanoscope in its place for such combinations.
The combination is called an astatic needle; it is used to detect very feeble currents.
Test the astatic needle, after you have it properly suspended, to convince yourself that it does not try to swing around in a N and S line.
Although some of the pairs of metals furnished so weak a current that it was necessary to use the astatic galvanoscope to study the current, all produced some current, and from the results can be formed an electromotive series (§ 301).
The astatic needle, for all its ingenuity, is little used; of incomparably more importance is that other magnetic device, the telephone.
To this end one needle is placed above another, the north pole of the first over the south pole of the second; the astatic needle formed by this union is much more sensitive than a simple needle.
The iron cylinder is thus converted into a strong magnet, attracting one of the poles, and repelling the other, and consequently deflecting the entire astatic system.
Such a helix is caused to stand between the two poles N'S' of an astatic system.
When it is so far sunk that its lower end rests upon the table, the upper end finds itself between the poles N´S´ of the astatic system.
It is manifest that if a second helix be placed between the poles SN with a cylinder within it, the action upon the astatic magnet may be exalted.
An astatic magnetic system used in conjunction with a mirror galvanometer gives a highly sensitive form of instrument (fig.
In a form of astaticneedle galvanometer devised by Professor A.
In course of time both the original form of single needle galvanometer and mirror galvanometer were improved by introducing the astatic principle and weakening the external controlling magnetic field.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "astatic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
