He invented the rheostat and improved the resistance balance, invented by S.
- A, antenna; P S, jigger or oscillation transformer; C, condenser; 0, Fleming oscillation valve; B, working battery; T, telephone; R, rheostat; E, earth-plate.
Suppose the key to be depressed, then a current flows through one winding of the differential relay to line and through the other winding and rheostat to earth.
Now if the values of the rheostat and condenser are adjusted so as to make the rise and fall of the outgoing current through both windings of the relay exactly equal, then no effect is produced on the armature of the relay, as the two currents neutralize each other's magnetizing effect.
The framework carrying the clamps is arranged so that a number of determinations may be made at one time, the wires from the clamps running from a rheostat, so arranged that currents of any strength may be used simultaneously.
23, representing the " differential " method, B is the sending battery, B 1 a resistance equal to that of the battery, R a rheostat and C an adjustable condenser.
When the key is in the middle position, that is, not making connexion with either the front or back contacts, the received currents pass through both coils of the relay and the rheostat; no interference is, however, felt from this extra resistance because, although the current is halved, it has double the effect on the relay, because it passes through two coils instead of one.
Trans., 18 93, P. 361), Whose Work Threw A Great Deal Of Light On The Failure Of Previous Observers To Secure Consistent Results, Corresponded To The Last Expression E 2 T/R, And Consisted In Regulating The Current By A Special Rheostat, So As To Keep The Potential Difference E On The Terminals Of The Resistance R Balanced Against A Given Number Of Standard Clark Cells Of The Board Of Trade Pattern.