US1653881A - Apparatus for varying the wave form of alternating current - Google Patents

Description

Dec. 27, 1927. 1,653,881

H. c. SNOOK APPARATUS FOR VARYING THE WAVE FORM OF ALTERNATING CURRENT Filed April 22, 1922 //7 vex? for:

Patented Dec. 2?, 1927.

UNITED STATES PATENT OFFICE.

HOMER C. SNOOK, 01 SOUTH ORANGE. NEW JERSEY, ASSIGNOR TO WESTERN ELEG- TRIO COMPANY, INCORPORATED, 0.1 NEW YORK, N. Y., A CORPORATION OI NEW YORK.

APPARATUS FOR VABYING THE WAVE FORM OF ALTERNATING CURRENT.

Application filed April 22, 1922. Serial No. 555,962.

This invention relates to a device for modifying the wave form of an alternating cur rent and particularly to a device of this character adapted for use in the exhaustion of vacuum tubes according to the cathode glow method disclosed in Patent No. 1,166,792, granted to applicant January 4, 1916.

In the copending application of J. B.

Johnson, Serial No. 481,505, filed June 30, 1921, now U. S. Patent 1,580,899, there is disclosed an apparatus for exhausting vacuum tubes in substantial accordance with the method disclosed in the above-noted patent, wherein are provided means for causing the alternate bombardment of the grid and plate electrodes and means for varying the energy delivered to the electrodes in the cathode glow according to their respective heat requirements.

It is an object of this invention to regu late the energy supplied to either of the electrodes without a corresponding variation oi the energy supplied to the other electrode.

it. further object of the invention is a simple and eficient apparatus for supplying energy to the electrodes and for varying the energy delivered to one electrode without varying the energy delivered to the other.

These objects are accomplished by providing two paths for supplying electrical energy to the electrodes so arranged that each path supplies current flowing between the electrodes in a direction opposite to the flow in the other path, causing the electrodes to receive current through said paths alternately and providing in each path means for varying the voltage thereof and the cur rent flow therethrough.

The drawing'discloses one embodiment 01' the invention.

A vacuum tube 1 to be exhausted is connected by means of a tubing 2 to a vacuum pump (not shown) and a valve 3 is provided in the tubing. The grid electrode 4. and the plate electrode 5 of the vacuum-tube 1 are electrically connected to the terminals of the secondary winding 6 of a transformer having primary windings 7 and 8. Adjacent terminals of the windings 7 and 8 are e1ectri- This arrangement provides two separate asymmetrical aths .for delivering energy from the transtormer to the electrodes 4 and 5, or, in other words, a separate path for each half wave of the alternating current due to the electromotive force induced in the coil 14:- The electromotive force induced in coil 14 causes a current to flow in the right hand path. This current can flow only in one direction due to the rectifier 11 and therefore flows only during one-half of the c cle. Similarly the current can flow in t e left hand path only in one direction which with respect to the coil 14 is opposite to the direction of current in the right-hand path. Thus, the left-hand circuit provides a path for one half wave and the right-hand circuit provides a path for the other half wave of the current due to the induced electromotive force in the coil 14.

The flow of current through the windings 7 and 8 induces in the winding 6 of the electrode circuit an alternating electromotive force which is the resultant of the separate electromotive forces induced by the alternate flow of direct current in windings 7 and 8. This electromotive force, which may be of 300 to 1000 volts produces in the electrode circuit an alternating current by means of which the electrodes 4 and 5 are alternately subjected to the cathode low.

The exhaustion of t e tube is accomplished in evacuating the tube to a vacuum of approximately one millimeter of mercury, after which an inert gas, such as ammonia, is introduced into the tube 1 and the valve 3 closed. Alternating current is supplied to the primary 15, thereby inducing an alternating electromotive force in the secondary 14. By virture of the separate paths, a half waveof the induced current alternately flows through the windin s 7 and 8. An alternatin electromotive orce is induced in the win ing 6, which alternately supplies to the grid and plate the energ necessary for the cathode glow. The gri and plate are thereby alternately bombarded with electrons supplied by the ionization of the as in the tube. The nitrogen formed by the ecomposition of the ammonia by the passage of the electron discharge between the grid and plate supplies electrons for the bombardment. After the electrodes have been denuded of their occluded gas the other steps of the method of applicants previously menticized patent are performed to evacuate the tu The energy supplied to the electrodes may be varied to heat the electrodes in accordance with their thermal capacity by regulating the amplitude of the currents flowing in the windings 7 and 8. The amplitude of the current flowing through windings 7 may be regulated by varying the number of turns of the winding 14 included in the left-hand circuit and by adjusting the resistance 12. Likewise the amplitude of the current flowing through thewinding 8 may be controlled by varying the number of turns of the winding 14 in the right-hand circuit and by adjusting the resistance 13. As the amplitude of the current in either the left or right hand may be varied independently of the other, the energy supplied to one of the electrodes in the cathode glow may be varied independently of the energy supplied to the other electrode.

The flow of current in the coil 7 will tend to induce in the coil 8 an electromotive force in a direction opposite to the electromotive force induced in the portion of the coil 14 to the right of the point 17. The algebraic sum of these two elect-romotive forces is less than the potential drop between the electrodes of the rectifier in the right-hand circuit and will not, therefore, be effective to cause a current flow in the right-hand circuit through the rectifier. The flow of current in the coil 8 will have a similar effect upon the lefthand circuit. Thus, the electromotive force induced ineither the coil 7 or 8 by the flow of current through the other of said coils, will have no effect upon the electromotive force induced in the electrode-circuit. The filament plays no part in the process of the invention.

It is, of course, understood that various modifications may be made in this apparatus without in any way departing from the spirit of the invention.

The invention claimed is:

1. In combination, a vacuum tube having two electrodes, a source of currrent, connections between said source and said electrodes forming a path for delivering current in one direction between said electrodes, connections between said source and said electrodes forming a path for delivering current in the opposite direction between said electrodes, and means in each path for determining the cur rent flow therethrough.

2. In combination, a source of alternating current, a vacuum tube having two electrodes, a path between said sourceand said two electrodes for one half wave of alternating current, a second path between said source and said two electrodes for the other half wave of alternatin current, and means individual to'a each pet for modfying the form of the. half wave flowing therethrough.

3. In combination, a vacuum tube having electrodes, a circuit connection between two electrodes, two separate paths for electric current inductively connected to said circuit,

means for passing current alternately through said paths to induce alternating current in the electrode circuit, and means for varying the current flow in each of said paths.

4. The combination of a vacuum tube having electrodes, a circuit connection between two electrodes, two circuits inductively connected with said electrode circuit, and means for passing current alternately through said circuits to produce alternating current in the electrode circuit.

5. The combination of vacuum tube having electrodes, means for alternately establishing a space discharge between said electrodes, in opposite directions and means for varying the energy delivered to either of said electrodes independently of the energy delivered to the other.

6. In combination, a vacuum tube having electrodes, an electrode circuit connecting two of said electrodes, two circuits inductive- 13 connected therewith, means for supplying alternating current to each of said circuits, and means in each of said circuits for preventing the How of one half wave of said current.

' 7. The combination of a vacuum tube having electrodes, an electrode circuit connecting two of said electrodes, 9. pair of circuits inductively connected therewith, a variable induction coil in each circuit, and a source of alternating current inductively connectedwith each of said coils.

8. In combination, an electrical device, a pair of circuits inductively connected therewith, 'a variable induction coil in each circuit, a uni-directional current flow device in each circuit, and a source of alternating current inductively connected with each of said coils.

9. In combination, an electrical device, a pair of circuits connected therewith, a variable induction coil in each circuit, a unidirectional current flow device in each cirwit, a variable resistance in each circuit, and a source of alternating current inductive- 1y connected with each of said coils.

10. The combination of an electrical device, a pair of circuits inductively connected therewith, a rectifier common to said circuits, an induction coil, part of which is a. por-

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