US2300451A - High-voltage power-supply system - Google Patents

Description

Nov. 3, 1942. A. H. R. SMITH HIGH-VOLTAGE POWER-SUPPLY SYSTEM Filed Sept. 21, 1940 2 Sheets-Sheet 1 FIG].

lNVENTOR ARTHUR. H.REESOR SMITH ATTORNEY Nov. 3, 1942. H. R. SMITH 2,300,451

HIGHVOLTAGE POWER-SUPPLY SYSTEM Filed Sept. 21, 1940 ZSheets-Sheet 2 Voltage INVENTOR v ARTHU H.REESOR SMT ATTORN EY Patented Nov. 3, 1942 HIGH-VOLTAGE POWER-SUPPLY SYSTEM Arthur H. Reesor Smith, Rutherford, N. 1., al-

signer to Hazeltine Corporation, a corporation of Delaware Application September 21, 1940, Serial No. 357,729

11 Claims.

The present invention relates to an improved high voltage power-supply system and, particularly, to a power-supply wherein a high unidirectional voltage is derived from a supply source of relatively low voltage by means of a vacuumtube oscillator.

It is frequently necessary to supply relatively high unidirectional voltages of the order of several thousand volts to electrical apparatus, for example, cathode-ray tubes of television systems. The energizing sources generally available are of relatively low voltage of the order of a few volts or a few hundred volts and it is, therefore, nec. essary to step-up the voltage of the source many times before the source may be utilized to energize such electrical apparatus.

It has heretofore been the general practice to develop such high energizing voltages from commercial alternating current supply mains by utilizing a conventional high voltage transformer and rectifier. A transformer operating at the low power frequencies necessarily must have a relatively large iron core which makes it of appreciable physical size and involves an expensive core construction. The windings of a transformer of this nature are of correspondingly large size and the required high voltage insulation between windings is rather elaborate and further increases the size and expense of construction of the transformer. A power-supply system of this character has the additional disadvantage that the filter required to remove the low-frequency alternating potential components of the rectified output is necessarily quite large, is expensive, and creates a dangerous hazard from electrical shockdue to the large amount of energy stored in the flltercondensers. Moreover, this type of high voltage power-supply system is capable of producing large magnetic fields which may interfere with the proper operation of the electrical apparatus unless the power supply is enclosed within heavy, cumbersome and expennating voltage of moderate amplitud but of relatively high frequency by the use either of a mechanical interrupter or of a vacuum-tube oscil-,

lator. The alternating potential thus obtained-is applied to a high voltage transformer, the output of which is rectified to derive the, required ,1

high voltage unidirectional potentiaL, While power-supply systems of this character avoid several of the disadvantages inherent in high volt age power-supply systems operating from commercial power-supply mains, they havein common with the latter the disadvantage that they require a separate rectifier tube of ex-pensive construction to enable the tube to withstand the high voltages of the system. The mechanical interrupter type of direct-to-alternating voltage converter additionally has the disadvantages, first,

harmonic components which may be capacitively coupled around the filter unit of the supply system to cause interference with the proper operation of tneelectrical apparatus energized thereby or other electrical apparatus.

It is an object or-the invention, therefore, to

provide a new and improved high voltage power-,

supply system which avoids one or more of the above-mentioned disadvantages and limitations of the prior art systems.

It is a further object of the invention to provide a high voltage power-supply system wherein the high voltage is obtained by the operation of a single vacuum tube suitably energized from a low voltage power-supply source.

It is a further object of the invention to provide a high voltage power-supply system of the type described wherein there may be obtained from a single vacuum tube not only a high unidirectional output voltage but additionally and simultaneously therewith output oscillations of saw-tooth wave form suitable for use, for example, in energizing the scanning system of a cathode-ray tube.

In accordance with one embodiment ofthe invention, a high voltage power-supply .system comprises a vacuum tube including an anode, a cathode and a control electrode and having an amplification factor less than unity. An anodecathode circuit and a control electrode-cathode circuit are provided for the vacuum tube. There is also provided means for connecting a space current source or source of exciting potential to the anode, and feed-back means coupling the anode-cathode and control electrode-cathode circuits to cause the vacuum tube to generate oscillations. There is also provided in the powersupply system a time-constant circuit included in the control electrode-cathode circuit for developing there across a unidirectional voltage by rectification of the generated oscillations, the voltage-transfer ratio of the feed-back means and the circuit values of the time-constant circuit being so proportioned with relation to the aforesaid amplification factor that the value of the unidirectional voltage is of a higher order of magnitude than that of the space current source. The power-supply system additionally includes an output circuit coupled to the timeconstant circuit for utilizing the developed unidirectional voltage.

In accordance with a further feature of the invention, the high-voltage power-supply system comprises an impedance network which includes two portions having unequal time constants, and means including the network for generating a periodic. voltage and for rectifying the periodic voltage to develop across the network a unidirectional potential having a component of saw-tooth wave form. The time constant of one of the network portions is proportioned to provide substantially the desired periodicity of the component of saw-tooth wave form and the time constant of the other of the portions is proportioned to derive from the developed unidirectional potential a substantially steady high unidirectional potential. A pair of output circuits are individually coupled to the portions of the network to utilize the component of saw-tooth wave form and the substantially steady high unidirectional potential.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to .the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring now to the drawings, Fig. i is a circuit diagram of a power-supply system embodying the invention; Figs. 2 and 3 respectively illustrate suitable constructions for the transformer and vacuum tube used in the Fig. 1 modification; Fig. 4 is a circuit diagram of a power-supply system embodying a modified form of the invention; Fig. 5 graphically represents certain voltage variations occurring at one point in the Fig. 4 arrangement and is used in explaining the opera tion thereof; and Fig. 6 illustrates a suitable arrangement of electrodes for the tube used in the Fig. 4 modification.

Referring now more particularly to Fig. 1, there is represented schematically a high voltage powersupply system embodying the present invention in a preferred form. The system includes a vacuum tube in having a cathode I I, a control electrode l3, and an interposed electron-permeable anode II. The tube In may be a conventional triode type of tube in which the conventional grid is used as the anode l2 and the conventional plate is used as the control electrode l3. In the following description and in the claims, the term "anode' is used in its accepted technical sense to designate a tube element which functions to collect electrons emitted by the cathode, irrespective of its physical construction, and, similarly, the term "control electrode is used in its accepted technical sense to designate a tube element which controls, in accordance with the magnitude of a potential applied thereto, the magnitude of the stream of electrons flowing from the cathode to the anode. The anode i2 is energized from a relatively low voltage supply source of space current or exciting potential +13 through the primary winding ll of a transformer IS. The circuit of the control electrode I3 is completed from the control electrode through the secondary winding I 6 of the transformer I5 and through a time-constant circuit, comprising a resistor I1 and shunt-connected condenser l 8, to the cathode II. The transformer l5 thus constitutes feedback means for coupling the anode-cathode and control electrode-cathode circuits to cause the vacuum tube to generate oscillations. The timeconstant circuit I], I8 is included in the control electrode-cathode circuit adjacent the common cathode terminal of the control electrode-cathode and anode-cathode circuits for developing thereacross a unidirectional voltage by rectification of the generated oscillations. An output circuit is coupled to the time-constant circuit l1, is through a pair of output terminals 19, IE to utilize the unidirectional voltage which is developed across the time-constant circuit by rectification in a manner presently to be explained. The cathode II is grounded to provide a common terminal for the individual circuits of the anode and control electrode, the time-constant circuit l1, [8, the source of space current +13, and the terminals I9, I!) of the output circuit.

Considering now the operation of the powersupply system, the transformer I5 is so poled that the feedback from anode [2 to control electrode [3 has a phase such that sustained oscillations are generated, the frequency of the oscillations being determined by the inductive reactance of the windings of transformer l5 and the lumped and distributed capacitances of the transformer and associated circuits. The transformer I5 has a high step-up voltage-transfer ratio from its primary to its secondary winding, whereby there is fed back from the anode circuit to the control-electrode circuit a substantial portion of the available anode circuit power and the controlelectrode peak voltage is many times that of the alternating voltage in the anode circuit. The control electrode I3 peak-rectifiers the oscillations produced in the winding [B to develop across the time-constant circuit l1, II a unidirectional voltage the polarity of which biases the control electrode l3 negatively.

Since the anode I2 is physically positioned between the cathode H and control electrode II, the amplification factor of tube I0 is quite low, preferably much less than unity. The circuit values of the time-constant circuit H, II, the amplification factor of tube Hi, the voltage-transfer ratio of transformer l5, and the ratio of inductive reactance to resistance of the controlelectrode circuit are all so relatively proportioned that the average value of the unidirectional voltage developed across the time-constant circuit II, II is of a materially higher order of magnitude than that of the space-current source +13. In proportioning these circuit constants, the ratio of the unidirectional voltage developed across the time-constant circuit l1, IE to that of the spacecurrent source +13 is increased in a number of ways; namely, by decreasing the value of the amplification factor of tube In, by increasing the ratio of inductive reactance to resistance of the control-electrode circuit, by increasing the stepup voltage-transfer ratio of the transformer i5,

and by increasing the value of the resistor I] up to that value of resistance at which tube I becomes somewhat unstablein operation due to blocking. The high unidirectional voltage de-' veloped across the time-constant circuit i1, i8 is applied to the output terminals l9, I!) of the power-supply system for utilization by suitable electrical apparatus, not shown.

Fig. 2 is a cross-sectional view of a suitable construction for the transformer l5 used in the Fig. l modification of theinvention. The transformer primary winding I4 is wound upon a tube of insulating material 20 and is separated from the transformer secondary winding l6 by a layer of insulating material 2i. A magnetic core 22, preferably formed of pressed, insulated, powdered iron particles, is positioned within the insulating tube 20 and having a plane of symmetry substantially coincident with that of the transformer windings. While this core may be omitted, it aids in increasing the ratio of the inductive reactance to resistance of the transformer windings and in increasing the coefiicient of coupling between them. The transformer windings as thus arranged have a high coefflcient of coupling so that the primary winding I4 may have a minimum self-inductance, which is advantageous when utilizing a low-mu oscillator tube which generally has a low anode-cathode resistance.

While, as previously stated, tube l0 may be a conventional triode with its grid used as the anode 12,, the high voltage power available from a power-supply system using a conventional triode is somewhat limited due to the limited power which the grid can dissipate without excessive overheating. Fig. 3 illustrates the construction of a triode type of tube capable of large power outputs and one particularly suitable for use in the Fig. l embodiment of the invention. The

tube is provided with an aligned row of indirectly heated tubular cathode elements 23 which are connected to a common cathode lead 24. Filamentary heaters extend throughout the lengths of the cathode elements 23 and are connected to heater lead-in conductors 25, 25. Supported on opposite sides of the cathode elements 23 is a' plate-like control electrode 26 and a plate-like anode 21. Electrical connection'to the control electrode 26 is made through a terminal 26 positioned at one end 01 the tube while connection,

to the anode 21 is completed through a lead-in conductor 29 which extends through the opposite end of the tube. This construction provides a tube of very low amplification factor and one in which the anode is adapted to dissipate appreciable quantities or heat. Additionally, the control electrode 26 is well insulated from other of the tube elements and is, therefore. capable of withstanding'thehigh voltages developed in the timeconstant 'eircuit- 11'. I6.

The source: or: space current +B is preferably a unidirectional; source although it may be an alternating current source, for example, the commercial power-supply mains. In the 1: Iter event, oscillations are produced only during a short portion oi each positive half-cycle or the spacecurrent source and the time-constant circuit l1, [6 should. therefore, have a time constant long in comparison to the period of one cycle or the space-current source if the ripple components due to the low frequency of the alternating curfun invention, the following values of circuit constants are given for the embodiment of the invention shown in Fig. 1 utilizing transformer and tube structures of the types illustrated in Figs, 2 and 3, respectively:

Inductance oi secondary winding 10 36 mil.

hem-i Inductance of primary wind ng 14' 22g mica- 0- en 1 Mutual inductance oi! transiormer 15 1 5 sailfihcnries Ratio of inductive reactance to resistance of secondary winding 10 75 at-125 kilocyclcs Condenser 18 50 micro. I? ic 'o a Resistor 17 p i 12 ti migoh s gogenig l of space-current source 15,, 485 stilts u e x Anode 12 and control electrode 13 {l in c h s u e Cathode. our e eme s li hl ng. 0 0 4 1 inch outside diameter spaced g) g 8 7' Anode-cathode licin 0.055 inch' Control electro e-cat ode spacing 0.120 inch Amplification factor 0.5 Fre uency of generated oscillations 190 film cyc es Un directional volta e derived ac line-constant circuit 17, i 8-- :3E:f-..- 6,100 volts modification simultaneously provides a high unidirectional voltage output and an alternating -vo1tasc ou pu o saw-tooth wave form which varies in magnitude periodically and substantial- 1y linearly between maximum and minimum values, the latter voltage output constituting a pulsating unidirectional voltage. Tube I6 is provided with an auxiliary control electrode to which is applied through terminals 3|, li a synchronizing voltage from any suitable synchronizlng 76 not shown. for controlling the p iodi ity o! the unidirectional voltage variations. Connected across the time-constant-circult i1, i6 are .a pair of output terminals 32, 62 for supplying the v l ped across the time-constant circuit l1, II to a first output circuit. The high unidirectional voltage output terminals I9, I9 of a second output circuit are also connected across the timeconstant circuit I1, l6 through a filter network 33 comprising series resistors 34, 35 and shunt GQndehsers I6, 66. Since the filter network 33 is connected in parallel with the time-constant circult i1, la, the network and the time-constant circuit comprise two portions of an impedance network II, II, II, 65, 36, 36. The first portion comprising the time-constant circuit l1, I6 01 rent source are to be eifectively suppressed in the derived high unidirectional voltage.

As illustrative of a specific embodiment of the relatively short time constant is coupled through an isolating impedance 34 to the second portion comprising the filter network elements 35, 36, 36 of relatively long time constant. The connections of tube ID in this modification are otherwise essentially similar to those of tube in in the Fig. 1 modification.

The operation of the two modifications differ, however, in that the circuit constants of the transformer 15, the circuit values of the timeconstant circuit i1, i8, the amplification factor of tube l0, and the magnitude of the space-current source +B are so proportioned that tube [0 rlcdically blocks after a few cycles of operation.

pulsating unidirectional voltage cathode-ray tube.

tive unidirectional voltage developed across the time-constant cricuit II, II by peak rectification of each group of oscillations periodically generated when the tube is in unblocked condition. Fig. 5 graphically represents the unidirectional voltage developed across the time-constant circult II, II. During the interval from ii to 2, tube II is in unblocked condition and generates several cycles of oscillations. These oscillations are peak-rectified by the control electrode i3 and charge the condenser II. The negative unidirectional voltage developed across the time-constant circuit l1, ll thus increases during this interval from a relatively low value E, at which anode current flows, to a relatively high value E1, at which the tube i0 is biased so far beyond cutofi that it blocks and anode current ceases to flow. During the time interval t-.--ta, the charge stored in the condenser I! discharges through the resistor l1 and the voltage across the time-constant circuit I1, I! thereupon decreases substantially linearly -with time from the voltage E1 to the voltage E. As soon as the voltage across the time-constant circuit i1, it has decreased sufficlently that anode current again begins to flow, tube l0 becomes unblocked and the system again commences to oscillate and the cycle is repeated.

The period at which tube ll blocks is determined prirnarily by the circuit values of the timeconstant circuit II, II, which are preferably ad- .iusted such that the period of blocking is slightly longer than the period of the synchronizing potential applied to the terminals M, II from the synchronizing source, not shown. The synchronising potential may be of conventional pulse wave form and be applied to the auxiliary control electrode 80 with positive polarity to trigger tube i0 just before oscillations would otherwise begin in the absence of the synchronizing potential. The synchronizing potential thus maintains the period of the alternating potential of saw-tooth wave form developed across the time-constant circuit H, il in synchronism with the synchronizing source, not shown.

The pulsating unidirectional potential of sawtooth wave form is applied to output terminals 32, 32 for utilization by any suitable electrical apparatus, for example, the scanning system of a The unidirectional potential developed across the time-constant circuit ii, iii is also applied to the filter network 33, which has a time constant long in comparison to the period of the saw-tooth potential and thus filters out the alternating component of the unidirectional potential to derive the average value thereof. The average value of the unidirectional potential is applied from the filter network to the output terminals 19, IS. The voltage-transi'er ratio of transformer ll,.the circuit values of the time-constant circuit I1, l0, and the amplification factor of tube iii are relatively so proportioned that the average value of the unidirectional potential is of a higher order of magnitude than that of the source +B.

Fig. 6 is a schematic representation of a suitable arrangement for the tube electrodes of tube l0 used in the Fig. 4 modification of the invention. The elements have a similar arrangement to those of the tube of Fig. 3 except that the auxiliary control electrode 30 is positioned between the cathode 23 and the anode 21. As thus arranged, the auxiliary control electrode 30 controls the magnitude of the electron stream from the cathode 23 to the anode 21.

This blocking action is effected by the high nega-' From the foregoing description of the invention, it will be evident that a power-supply system embodying the invention provides in a simple and inexpensive apparatus a source of high uni-' directional voltage derived from a relatively low voltage power-supply source of either the alternating or direct voltage types. Moreover, the magnitude of the unidirectional voltage may easily be controlled by suitable adjustment or selection of one or more of the circuit constants of the high voltage power-supply system. The modified form of the invention of Fig. 4 has the additional advantage that a periodic voltage of saw-tooth wave form may be simultaneously obtained with the high unidirectional voltage.

It will be evident to one skilled in the art that tube lll or l0 may be the local oscillator tube of a superheterodyne type of carrier-signal receiver, the control-electrode circuit being tuned in conventional manner to generate oscillations of suitable heterodyne frequency.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A high voltage power-supply system comprising, a vacuum tube including an anode, a cathode, and a. control electrode and having an amplification factor less than unity, an anodecathode circuit and a control electrode-cathode circuit for said vacuum tube, said circuits being so proportioned that said control-electrode circuit has a maximum ratio of inductance to resistance, means for connecting a space-current source to said anode, feed-back means coupling said anode-cathode and said control electrode- 7 cathode circuits to cause said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross a unidirectional voltage by rectification of said generated oscillations, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the value of said unidirectional voltage is of a. higher order of magnitude than that of said source, and an output circult coupled to said time-constant circuit for utilizing said unidirectional voltage.

2. A high voltage power-supply system comprising, a vacuum tube including an anode, a cathode, and a control electrode and having an amplification factor less than unity, an anodecathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a space-current source to said anode, feedback means coupling said anode-cathode and said control electrode-cathode circuits to cause said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross a unidirectional voltage by rectification of said generated oscillations, the voltage-transfer ratio of said feed-back means and the circuit values of said timemonstant circuit being so proportioned With relation to said amplification fac tor that the value of said unidirectional voltage is of a higher order of magnitude than that of said source, and an output circuit coupled to said time-constant circuit for utilizing said unidirectional voltage,

3. A high voltage power-supply system comprising, a vacuum tube having a cathode, a control electrode, and an interposed electron-permeable anode, an anode-cathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a space-current source to said anode, feed-back means coupling said anode-cathode and said control electrodecathode circuits to cause said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross a unidirectional voltage by rectification of said generated oscillations, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the value of said unidirectional voltage is of a higher order of magnitude than that of said source, and an output circuit coupled to said time-constant circuit for utilizing said unidirectional voltage.

4. A high voltage power-supply system comprising, a vacuum tube having a cathode, and having an anode and control electrode disposed on opposite sides of said cathode, an anodecathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a space-current source to said anode, feedback means coupling said anode-cathode and said control electrode-cathode circuits to cause said vacuum tube to generate oscillations, a timeconstant circuit included in said control electrode-cathode circuit for developing thereacross a unidirectional voltage by rectification of said generated oscillations, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the value of said unidirectional voltage is of a higher order of magnitude than that of said source, and an output circuit coupled to said time-constant circuit for'utilizing said unidirectional voltage.

5. A high voltage power-supply system comprising, a vacuum tube including an anode, a

cathode, and a control electrode and having an amplification factor less than unity, an anodecathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a space-current source to said anode, feedback means comprising a transformer having a primary winding coupled to said anode-cathode circuit and a secondary winding coupled to said control electrode-cathode circuit. for causing said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross a unidirectional voltage by rectification of 'said generated oscillations, the voltagetransfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the value of said unidirectional voltage is of a higher order of magnitude than that of said source, and an output circuit coupled to said time-constant circuit for utilizing,

said unidirectional voltage.

6. A high voltage power-supply system comprising, a vacuum tube including an anode, a control electrode, and a cathode and having an amplification factor less than unity, individual circuits for said anode and said control electrode including a common cathode terminal, means for connecting a space-current source between said common terminal and said anode; feed-back means coupling said anode and said control electrode to generate oscillations, a time-constant circuit included in said control-electrode circuit adjacent said common terminal for developing a unidirectional voltage by rectification, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the value of said unidirectional voltage is of a higher order of magnitude than that of said source, and an output circuit coupled to said time-constant circuit for utilizing said unidirectional voltage.

'7. A high voltage power-supply system comprising, an impedance network including two portions having unequal time constants, means including said network for generating a periodic voltage and for rectifying said periodic voltage to develop across said network a unidirectional potential having a component of saw-tooth wave form, the time constant of one of said network portions being proportioned to provide substantially the desired periodicity of said component of saw-tooth wave form and the time constant of the other of said portions being proportioned to derive from said developed unidirectional potential a substantially steady high unidirectional potential, and ,a pair of output circuits individually coupled to said portions of said network to utilize said component of saw-tooth wave form and said substantially steady high unidirectional potential. 4

8. A high voltage power-supply system comprising, an impedance network having a first portion of relatively short time constant coupled through an isolating impedance to a second portion of relativelylong time constant, means including said network for generating a periodic voltage and for rectifying said periodic voltage to develop across said first portion a unidirectional potential having a component of sawtooth wave form, the time constant of said first portion being proportioned to provide substantially the desired periodicity of said component of saw-tooth wave form and the time constant of said second portion being proportioned to derive from said developed unidirectional potential a substantially steady high unidirectional potential, and a pair of output circuits individually coupled to said portions of said network to utilize said component of saw-tooth wave form and said substantially steady high unidirectional potential.

9. A high voltage power-supply tystem comprising, a vacuum tube including an anode, a cathode, and a control electrode, an anodecathode circuit and a controlelectrode-cathode circuit for said vacuum tube, means for connecting a source of exciting potential to said anode, feed-back means coupling said anode-cathode and said control electrode-cathode circuits to cause said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross by rectification of said generated oscillations a unidirectional voltage varying in magnitude periodically and substantially linearly between maximum and minimum values, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the average value of said unidirectional voltage is of a higher order of magnitude than that of said source, a first output circuit coupled to said time-constant circuit for supplying a first utilizing circuit with said periodic unidirectional voltage, means coupled to said time-constant circuit for deriving from said developed periodic voltage a substantially steady unidirectional voltage having said average value, and a second output circuit coupled to said lastnamed means for supplying a second utilizing circuit with said unidirectional voltage having said average value.

10. A high voltage power-supply system comprising, a vacuum tube including an anode, a cathode, and a control electrode, an anodecathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a space-current source to said anode, feedback means coupling said anode-cathode and said control electrode-cathode circuits to cause said vacuum tube to generate oscillations, an impedance network comprising two portions of unequal time constants included in said control electrode-cathode circuit for developing across a first of said networkportions by rectification of said generated oscillations a unidirectional voltage varying in magnitude periodically and substantially linearly between maximum and minimum values, the voltage-transfer ratio of said feed-back means, the circuit values of said first network portion, and the amplification factor of said tube being so proportioned that the average value of said unidirectional voltage is of a higher order of magnitude than that of said source, a first output circuit coupled to said first network portion for utilizing said periodic unidirectional voltage. the second of said network portions be-' ing proportioned to have a time constant long compared to the period of said voltage variations, and a second output circuit coupled through ;aid

second network portion to said first network portion for utilizing the average value of said unidirectional voltage.

11. A high voltage power-supply system comprising, a vacuum tube including an anode, a cathode, a control electrode and an auxiliary control electrode, an anode-cathode circuit and a control electrode-cathode circuit for said vacuum tube, means for connecting a source of exciting potential to said anode, feed-back means coupling said anode-cathode and said control electrode-cathode circuits to cause said vacuum tube to generate oscillations, a time-constant circuit included in said control electrode-cathode circuit for developing thereacross by rectification of said generated oscillations a unidirectional voltage varying in magnitude periodically and substantially linearly between predetermined maximum and minimum values, the voltage-transfer ratio of said feed-back means, the circuit values of said time-constant circuit, and the amplification factor of said tube being so proportioned that the average value of said unidirectional voltage is of a higher order of magnitude than that of said source, means coupled to said auxiliary control electrode for controlling the periodicity of said unidirectional voltage variations, a first output circuit coupled to said time-constant circuit for supplying a first utilizing circuit with said periodic unidirectional voltage, means coupled to said time-constant circuit for deriving from said developed periodic voltage a substantially steady unidirectional voltage having said average value, and a second output circuit coupled to said last-named means for supplying a second utilizing circuit with said unidirectional voltage having said average value,

A. H. REESOR SMITH.

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