US2213855A - Relaxation oscillator - Google Patents

Relaxation oscillator Download PDF

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Publication number
US2213855A
US2213855A US170398A US17039837A US2213855A US 2213855 A US2213855 A US 2213855A US 170398 A US170398 A US 170398A US 17039837 A US17039837 A US 17039837A US 2213855 A US2213855 A US 2213855A
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United States
Prior art keywords
condenser
electrode
anode
grid
cathode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US170398A
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English (en)
Inventor
Black Donald Harrison
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International Standard Electric Corp
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International Standard Electric Corp
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Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
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Publication of US2213855A publication Critical patent/US2213855A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
    • H01J43/02—Tubes in which one or a few electrodes are secondary-electron emitting electrodes
    • H01J43/025—Circuits therefor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/10—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only
    • H03K4/12—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth voltage is produced across a capacitor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/10—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only
    • H03K4/12—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth voltage is produced across a capacitor
    • H03K4/18—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth voltage is produced across a capacitor using a single tube exhibiting negative resistance between two of its electrodes, e.g. transitron, dynatron

Definitions

  • This invention relates to relaxation oscillation generators, that is arrangements in which an impulse or succession of impulses of desired wave form is obtained by the suitable charging and discharging of a condenser.
  • Such oscillators are frequently used to provide linear time bases for cathode ray oscillograph work and two such oscillators are normally employed when a cathode ray tube is used to receive television transmissions.
  • One common method of producing the required relaxation or saw toothed oscillations is by means of gas discharge tubes, either of the diode or triode type.
  • gas discharge tubes either of the diode or triode type.
  • the use of such discharge tubes has a number of disadvantages and circuits using socalled hard valves have therefore been proposed.
  • An object of the invention is to provide an improved method of employing a hard valve to obtain relaxation oscillations.
  • a condenser in a relaxation oscillator is adapted to be discharged over a circuit comprising a secondary electron stream set up in a vacuum tube.
  • a condenser which is ⁇ adapted to be charged through an impedance is connected' across a primary discharge path of a tetrode or four electrode valve and the tetrode is connected so that when the condenser voltage is large a secondary discharge path is set up in the tetrode by secondary electrons reaching the positive electrode of the primary discharge path.
  • the current in the secondary discharge path is utilised to provide a voltage for reducing the potential of the control grid of the tetrode so that the impedance of the discharge paths is rapidly reduced and the condenser rapidly discharged.
  • a variable impedance suitable for the rapid discharge of a condenser in a relaxation oscillation generator comprises a screen-grid Valve subject to a control voltage adapted to vary the screen grid potential and thereby to vary the secondary emission from the anode and means for controlling the control-grid potential according to the anode current to increase and decrease the primary electron stream when the secondary emission is respectively increasing and decreasing.
  • a relaxation oscillator comprises a condenser C1 adapted to be charged over a resistance R1 from a direct cur- (Cl. Z50-36) rent supply source connected between the terminals HT+ and EIT-
  • The' condenser is intermittently discharged by means of the valve V.
  • the valve V is of the tetrode screen-grid type and is such that its anode is capable of emitting secondary electrons to such an extent that the number of secondaries is greater than the number of primaries.
  • the anode may be formed or treated in any of the ways known in the construction of vacuum tubes known as electron multipliers and utilising the secondary emission from an electrode bombarded by primary electrons.
  • the anode may comprise a coating of caesium oxide on a surface of silver.
  • the anode potential is adjusted by means of a tapping on a resistance R4. and is set at some convenient value, say 100 volts.
  • the rst, or control, grid potential is determined by -a tapping on the resistance R5.
  • the resistances R5 and R4 are connected in series with a third resistance Ra between the supply terminals.
  • the condenser C1 charges up through the resistance R1. No current passes in the valve V until the voltage across C1 reachesl .such a value that current begins to flow from the second, or screen, grid of the valve to the cathode.
  • the potential at which this current starts is determined by the potential on the control grid.
  • When electrons begin to arrive at the screen grid others will also arrive at the anode and these will eject secondary electrons from the anode which will be collected by the screen.
  • current will ilow from screen to anode, via the resistances R2 and R4 and the condenser C1.
  • the current flowing in R2 causes a positive impulse to be applied to the first grid over the condenser Cz.
  • the condenser C1 is discharged very rapidly. It should be noted that the condenser is discharged over two paths; (l) by the primary electrons flowing from cathode to screen, and (2) by the secondary electrons flowing from anode to screen. If the anode is so treated that it emits a copious supply of secondary electrons, this latter discharge path may be made very eective.
  • Re is a decoupling resistance to prevent the impulses to the control grid from. owing to the cathode viaV R5.
  • C3 and C4 are reservoir condensers of convenient value.
  • Synchronising impulses may be introduced into the control grid circuit in any known manner in order to initiate vthe discharge, as is the practice in most relaxation oscillators.
  • 'I'he condenser C1 may be charged through a saturated diode or through a pentode valve operating on the vsaturation portion of its characteristicin order to obtain a more uniform charging rate.
  • the device may also be followed by amplifying and phase inverting stages if required.
  • relatively charging and relatively discharging are used hereinafter to denote opposite changes in the charge of a condenser without regard to whether'the absolute potential difference across the condenser is greater in the relatively lcharged or the relatively discharged state.
  • absolutely charging and absolutely discharging are used when it is intended to distinguish speciiically between changes of charge which vary the total potential diierence respectively away from and toward absolute zero.
  • Relaxation oscillation generator comprising a vacuum tube, a thermionic cathode, a control grid, a iirst positive electrode and a second positive electrode therein, a condenser connected between said cathode and said rst positive electrode, a circuit for relatively charging said condenser, means for polarising said second positive y electrode and said control grid so that primary and secondary electronslow to said rst positive electrode respectively from the cathode and saidv other positive electrode responsive to said condenser becoming charged and means for setting up a voltage proportional to the current to said second positive electrode and for utilising this voltage to modify the potenti-a1 of said control grid to increase the primary electron stream.
  • Relaxation oscillation generator comprising a direct current supply source, a condenser and an impedance connected in series across said source for the absolute charging of said condenser and an absolute discharging circuit for said condenser, said discharging circuit comprising a vacuum tube, having a thermionic cathode, a control grid, v an'a'node and a lfourth electrode therein, said condenser being connected between said cathode and said fourth electrode, means for applying between said cathode and said anode a voltage lessA than that of the supply source, means for biasing said control grid so that until said condenser has a substantial absolute charge substantially no current flows through said tube, a resistance in said ⁇ anode connection and a condenser connected between said anode and said control grid.
  • Relaxation oscillation generator comprising a vacuum tube having a thermionic cathode, a control grid, a third electrode and a fourth-electrode therein, meansvfor biasing said third electrode more positively than either said cathode or said control grid, ka, condenser, means for relatively charging said condenser, means for biasing said fourth velectrode to such a potential with respect lto said third electrode that secondary electrons flow from saidthird electrode to said fourth electrode and a circuit lfor relatively disg charging said condenser comprising a space conduction path extending from ⁇ said fourth electrode to said cathode and third electrode.
  • Relaxation oscillator according to claim A4 further comprising an impedance in series with said third electrode in said circuit, and a coupling condenser connected between ⁇ said Vthird electrode and said control grid.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Details Of Television Scanning (AREA)
  • Testing Relating To Insulation (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Phenolic Resins Or Amino Resins (AREA)
  • Particle Accelerators (AREA)
  • Electron Sources, Ion Sources (AREA)
  • X-Ray Techniques (AREA)
  • Electron Tubes For Measurement (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
  • Microwave Tubes (AREA)
US170398A 1936-11-16 1937-10-22 Relaxation oscillator Expired - Lifetime US2213855A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB31344/36A GB485120A (en) 1936-11-16 1936-11-16 Improvements in or relating to relaxation oscillation generators
GB24478/38A GB518240A (en) 1936-11-16 1938-08-19 Improvements in or relating to relaxation oscillation generators
GB30523/38A GB520411A (en) 1936-11-16 1938-10-21 Improvements in or relating to relaxation oscillation generators

Publications (1)

Publication Number Publication Date
US2213855A true US2213855A (en) 1940-09-03

Family

ID=32073925

Family Applications (3)

Application Number Title Priority Date Filing Date
US170398A Expired - Lifetime US2213855A (en) 1936-11-16 1937-10-22 Relaxation oscillator
US288935A Expired - Lifetime US2270405A (en) 1936-11-16 1939-08-08 Relaxation oscillation generator
US301390A Expired - Lifetime US2199278A (en) 1936-11-16 1939-10-26 Electron discharge device

Family Applications After (2)

Application Number Title Priority Date Filing Date
US288935A Expired - Lifetime US2270405A (en) 1936-11-16 1939-08-08 Relaxation oscillation generator
US301390A Expired - Lifetime US2199278A (en) 1936-11-16 1939-10-26 Electron discharge device

Country Status (5)

Country Link
US (3) US2213855A (de)
DE (3) DE901827C (de)
FR (3) FR828278A (de)
GB (3) GB485120A (de)
NL (3) NL55138C (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2459187A (en) * 1946-10-01 1949-01-18 Columbia Broadcasting Syst Inc Deflection circuit for cathode-ray tubes
US2644093A (en) * 1945-01-24 1953-06-30 Us Sec War Frequency stabilizing circuit
US2790904A (en) * 1954-06-24 1957-04-30 Goodyear Tire & Rubber Sawtooth waveform generator
DE1091607B (de) * 1958-08-14 1960-10-27 Philips Nv Schaltungsanordnung zum Erzeugen einer saegezahnfoermigen Spannung veraenderbarer Frequenz

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB522637A (en) * 1938-12-16 1940-06-24 Eric William Bull Improvements in or relating to generators of electric wave-forms
US2456029A (en) * 1942-07-30 1948-12-14 Rca Corp Thermionic tube circuits
NL75432C (de) * 1943-06-25
NL138132C (de) * 1944-04-19
US2462078A (en) * 1944-09-15 1949-02-22 Int Standard Electric Corp Oscillation generator
US2521762A (en) * 1945-12-19 1950-09-12 Standard Telephones Cables Ltd Saw-tooth oscillator
US2786197A (en) * 1946-03-29 1957-03-19 Sperry Rand Corp Ranging system
US2510101A (en) * 1946-09-28 1950-06-06 Graham Mfg Corp Electric percussion welding system
US2675471A (en) * 1950-04-13 1954-04-13 Gen Electric Integrating circuit
US2631233A (en) * 1950-12-28 1953-03-10 Ibm Secondary emission trigger circuit
US2794122A (en) * 1952-12-26 1957-05-28 Rca Corp Voltage correction circuits
US2870411A (en) * 1953-04-21 1959-01-20 Honeywell Regulator Co Frequency modulated oscillator
BE534902A (de) * 1954-01-22
NL239763A (de) * 1958-06-02

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2644093A (en) * 1945-01-24 1953-06-30 Us Sec War Frequency stabilizing circuit
US2459187A (en) * 1946-10-01 1949-01-18 Columbia Broadcasting Syst Inc Deflection circuit for cathode-ray tubes
US2790904A (en) * 1954-06-24 1957-04-30 Goodyear Tire & Rubber Sawtooth waveform generator
DE1091607B (de) * 1958-08-14 1960-10-27 Philips Nv Schaltungsanordnung zum Erzeugen einer saegezahnfoermigen Spannung veraenderbarer Frequenz

Also Published As

Publication number Publication date
FR50956E (fr) 1941-05-19
DE938560C (de) 1956-02-02
FR50872E (fr) 1941-04-18
DE941145C (de) 1956-04-05
NL63342C (de) 1949-06-15
NL55897C (de) 1944-03-15
US2270405A (en) 1942-01-20
GB485120A (en) 1938-05-16
GB518240A (en) 1940-02-21
GB520411A (en) 1940-04-23
US2199278A (en) 1940-04-30
FR828278A (fr) 1938-05-13
NL55138C (de) 1943-09-15
DE901827C (de) 1954-01-14

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