US1552219A - Vacuum-tube circuits - Google Patents

Description

Sept. 1, 1925. 1,552,219

G. G. MERCER VACUUM TUBE CIRCUITS Filed April 2.3. 1220 inx/e nboi-"i George Mercer,

flaw/ i His Attorney-- Patented Sept. 1, 1925.

UNITED "STATES V A 1,552,219 PATENT OFFICE.

oEoaoE GLENN MERCER, or SCEENEGTAIDY, nEw YoEx', assionon. T0 GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

VACUUM-TUBE CIRCUITS.

Application filed April 23, 1920. Serial No. 375,976.

If an electron discharge device comprising an electron emitting cathode and an anode enclosed in an evacuated receptacle.

has a source of potential connected between cathode and anode, a current will flow between cathode and anode which is carried.

by. means of electrons emitted from the cathode. The current flowing between the electrodes may be controlled ,or varied in amplitude by means of a magnetic" field set up in the receptacle in a direction at right angles to the electrostatic field between the electrodes. To control the current in this way requires a magnetic field of considerable magnitude, that is, no variation will be produced in the current-unless a magnetic field of a predetermined stren th is set up in the space between the electro es.

When, however, a magnetic field of the required strength is set up in the space between the electrodes a small variation in the strength of this magnetic field will produce a large variation in the strength of the current flowing between the electrodes. In the operati n of such devices in the past it has been cus mary to provide a separate source of current for producing a constant magnetic field of such a value that a variable magnetic field superimposed thereupon will produce the desired changes in the current. This constant magnetic field is usually termed the polarizing field.

' The object of my invention is to eliminate the necessity for the use of a separate source of current for furnishing the polarizing field and to permit of the production of this polarizing field by means of the electron current flowing between the cathode and anode.

In carrying my invention into effect I cause the current which flows between the electrodes to pass through a coil or coils surrounding the tube. Altho in the 'usual operation of the device this current is caused to vary, I have found that by shunting these coils by means of a condenser of i proper size; for bypassing the variable component of the current in the circuit a substantially constant current will flow through the coils and as a result a polarizing field of substantially constant value will be produced.

The novel features which I believe to be characteristic of my invention are set forth 'with particularity in the appended claims.

My invention itself, however, will best be understood by referenceto the following description taken in connection with the ac companying drawings in which Figs. 1, 2

and 3 illustratediagrammaticallythree dif ferent' circuit arrangements in w vention may be. employed.

As indicated in Fi 1, an electron discharge device is emp oyed comprising an oh my inevacuated receptacle 1, which is preferably of tubular form and which contains a filamentary cathode 2. and an anode 3 of cylmdric'al form surrounding the cathode.

A source of current 4 is connected tov the two terminals of the cathode 2 for heating it to incandescence to cause it to emit electrons for carrying. current across the evacuated space between the two electrodes. An external circuit between electrodes 2 and 3 includes a source of direct current 5, inductances represented conventionally at 6 and 7 but which actually are wound around the receptacle 1, and an inductance 8 and a variable tuning capacity 9 in shunt to in du'ctance 8. Inductances 6 and are shunted by a condenser 10. 'The current which flows between cathode 2 and anode 3, through coils 6 and 7, produces a constant magnetic field in the space between the electrodes which is in a direction parallel to the axis ofthe tube or at right angles to the electrostatic field between the electrodes. Coils 6 and 7 and source 5 are so propor-' ti'oned that this constant magnetic field will have a predetermined desired value. The coil 8 is coupled to a coil 11 in series with the antenna 12,. and a second coil 13, which is also in series with the antenna, surrounds the receptacle 1. This coil 13 produces a second magnetic field in receptacle 1 which sired in the receptacle 1.

is bypassed through condenser 10. As a result, the current flowing in coils 6, 7, will be substantially constant and-therefore will maintain the constant polarlzlng field de- In Fig. 2 I have shown another modification of my invention in which devices of the type in question are emplo ed as'amlifiers. In this case the current w ich is to e amplified is supplied to the coil 14 which surrounds the receptacle '1 and the magnetic field produced by the current to be amplified produces corresponding variations in the current through the device. In lthis case, as in Fig. 1, the variable component of the current through the device is bypassed through the condenserlO and the current flowing through the coils 6 and 7 is substan' tially constant. The variable com onent of the current in the plate circuit 0 the first device is supplied by means of a transformer 15 to the input coil 16 of a second device 17, which is connected up in a similar manner. The variable component in the plate circuit of this second device is in turn impressed by means of transformer-18 upon the output circuit 19, which may contain suitable devices for giving an indication of the amplified current or may supply amplified current in the input circuit of still another device as may be desired. The input circuit of the second device 17 may be tuned by means of a variable condenser 20 if desired.

The arran ement shown in Fig. 3 is similar to that shown in Fig. 2 with the exception that the entire current in the plate circuit of the first device is supplied to the input coil 16 of the second. Tn this case as in the preceding case, the input circuit of the second device may be tuned by means of the condenser 21. I have indicated in the plate circuit of the device 17 a transformer 22 for supplying the amplified current to the output circuit. This expedient may be employed if desired as there is no advantage in supplying to the output circuit of the lastdevice the direct current component of a plate current.

While I have indicated and described only three circuit arran ements in which my invention may be 'uti ized, it is apparent that a great variety of modifications in the cirdevice comprising anv evacuated receptacle cuit arangenents employed 'as well as in the specific iorm of apparatus used may he made without departing from the scope of my invention as set forth in the appended claims. I

What -I claim as new and desire to secure by Letters Patent of the United States, is

1. The combination in an apparatus of the class described of an electron discharge containing a cathode adapted to'emit electrons and an anode, an external circuit between said cathode and anode containing a source of current and means for producing by current flowing in said circuit a substan-, tially constant magnetic field in the space between said electrodes.

2. The combination inpan apparatus of the class described of an electron discharge device comprising an evacuated receptacle containing a cathode adapted to emit electrons and an anode, an external circuit be tween said cathode and anode containing a source of current, an inductive winding surrounding said receptacle and connected in said external circuit to receive current there from, means for varying the current in said circuit and means for maintaining a substantially constant current in said inductive winding. $5

3. The combination in an apparatus of the class described of an electron discharge device comprising an evacuated receptacle containing a cathode adapted to emit elec trons andan anode, an externai circuit bev100 tween said cathode and anode containing a source of current, an inductive winding sur rounding said receptacle and connected in said external circuit, means for varying the current in saidcircuit and a condenser in 105 shunt to said inductive winding for bypassmg the variable component of the current in said external circuit.

4. The method of. operating an electron I discharge device having an electron emitting cathode and an anode enclosed in an evacuatedreceptacle, which consists in applying a potentlal to said electrodes to produce a flow of current between said electrodes; producmg by means of current flowing between sald electrodes, a substantially constant magnetic field between said electrodes in a direction substantially at right angles to the electrostatic field between said electrodes and producing a variable magnetic field whlch is superimposed upon said constant magnetic field.

5. The method of operating an electron discharge device having an electron emitting cathode and an anode enclosed in an evacuated receptacle which consists in applying a potential to said electrodes to produce a flow of current between said electrodes, producing a variable magnetic field in the space between said electrodes for varying the current between said electrodes, and producing by means of a constant component of the current between said electrodes 'a substantially constant magnetic field in the space between said electrodes.

6. The combination inan apparatus of the type described of an electron discharge device comprising a cathode adapted to emit electrons and a cooperating anode, an external circuit between said vcathode and anode containing a source of current, means for varying the currentflo'wing in said curcuit, and means for producing by current flowing in said circuit a substantially constant magnetic field in the space between said electrodes. 1

7. The combination in an apparatus of the type described of an electron discharge device comprising a cathode adapted to emit electrons and a cooperatin anode, an external circuit between sa1d cathode and anode containing a source of current, means for varying the current flowing in said circuit, an inductance included in saidcircuit, and means for maintaining a substantially constant current in said inductance, and producing by such current a substantially constant magnetic field in the space between said electrodes.

8. The combination in an apparatus of the type described of an electron discharge device comprising a cathode adapted to emit electrons,- and a cooperating anode, an external circuit between said cathode and anode containing a source of current, means for varying the current flowin in said Circuit, an inductive windingincluded in said circuit, means for maintaining a substantially constant current in said inductive winding and therebyproducing a substantially constant ma etic field in the space between said electro es, said means comprising a connection in shunt to said inductivewinding for by-passing the variable component of the current in said external circuit. i

9. The combination in an apparatus of the type described of an electrondischarge device comprising a cathode adapted to emit electrons, and a cooperating anode, an external circuit between said cathode and anode containing a source of current, means for varying the current flowing between said cathode and anode, an inductive winding included in said circuit, means for maintaining a substantially constant current in said inductive winding and producing by such current a substantially constant magnetic field in the space between said electrodes, said means comprising a shunt connection in the circuit between cathode and anode for rent flowing between cathode and anode.

In witness whereof, I have hereunto set my hand.

GEORGE GLENN MERCER.

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