US2308997A - Electric wave translation - Google Patents

Electric wave translation Download PDF

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Publication number
US2308997A
US2308997A US391376A US39137641A US2308997A US 2308997 A US2308997 A US 2308997A US 391376 A US391376 A US 391376A US 39137641 A US39137641 A US 39137641A US 2308997 A US2308997 A US 2308997A
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United States
Prior art keywords
cathode
voltage
stage
drift
amplifier
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
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US391376A
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English (en)
Inventor
Stewart E Miller
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AT&T Corp
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Bell Telephone Laboratories Inc
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Filing date
Publication date
Priority to NL67373D priority Critical patent/NL67373C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US391376A priority patent/US2308997A/en
Application granted granted Critical
Publication of US2308997A publication Critical patent/US2308997A/en
Priority to FR948178D priority patent/FR948178A/fr
Priority to GB20137/47A priority patent/GB625379A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/34—DC amplifiers in which all stages are DC-coupled
    • H03F3/36—DC amplifiers in which all stages are DC-coupled with tubes only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0046—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00
    • G01R19/0076—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00 using thermionic valves
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B11/00—Automatic controllers
    • G05B11/01—Automatic controllers electric
    • G05B11/012—Automatic controllers electric details of the transmission means
    • G05B11/013—Automatic controllers electric details of the transmission means using discharge tubes

Definitions

  • This invention relates to electric wave amplifiers and more particularly, although in its broader aspects not exclusively, to sensitive ampl'ifiers adapted for the amplification of direct current or current of low frequency of the order of a few cycles per second.
  • Fig. 1 illustrates schematically an embodiment of the invention comprising an amplifier stage in which cathode drift eflect is substantially completely neutralized;
  • Fig. 2 illustrates a two-stage amplifier comprising an input stage of the kind shown in Fig. 1 and a second stage that is of a modified form adapted ior substantial reduction of cathode 'drift effect; and it further illustrates an advantageous cascading of the two types of stages;
  • Fig. 3 illustrates an improved electronic voltage regulator in accordance with the invention embodying also a direct current amplifier with reduced cathode drift effect.
  • ' a unitary straight cathode 2 that is uniformly mating in character rather than unidirectional? and of a frequency that may be of'the order I of a fraction of a cycle to a few cycles per second.
  • the principal object of the present invention is to eliminate or substantially reduce the efiect of cathode drift.
  • Another object is to increase the accuracy and effectiveness of an electronic voltage regulator.
  • a further object of the invention is to provide an improved multistage amplifier adapted for the amplification of direct or low frequency currents.
  • Opposite or surrounding difierent longitudinal portions of the cathode are the respective grids or control electrodes d-and 5, and
  • anodes d and i beyond or surrounding these are the respective anodes d and i. It will be convenient to refer to grid 5 and anode 8 as comprising the amplifier section of the discharge device and to grid 5 and anode i as comprising the balancer sec tion. 'In further explanation of the essential nature of the discharge device, it may be said that the latter provides for two discharge paths between the common cathode and the respec tive anodes and that the discharges or dise paths are afiected alike, either equally or in fixed proportion, by cathode drift. Although the two discharges are derived from difierent portions of 7 the cathode, which conceivably might assume drift efiects are or may be observable in the two sections of the discharge device.
  • the currents to be amplified are applied to the input of the amplifier across a coupling resistor I0.
  • One input terminal is connected to the control grid 4, and the other input terminal, which may be grounded, is connected through series resistors RI and R2 to cathode 2.
  • Grid is tied to the junction of resistors RI and R2.
  • Anode 6 is connected directly to one output terminal of the amplifier and it is connected through coupling resistor R3 to the positive terminal of a plate voltage source here represented as a battery II, the negative terminal of which is grounded.
  • Anode I is connected to an intermediate tap on battery II.
  • the cathode drift is represented by a fictitious voltage source I2 disposed in the lead to cathode 2.
  • the voltag V of this source may be assumed to vary in such manner as to have the same efiect on the potential of the cathode, relative to grids 4 and 5, as would the cathode drift which the source I2 represents. Implicit is the assumption that the parameters of the two sections of the discharge device are exactly alike so that the effective cathode drift voltage is the same for both sections, but this condition is unnecessary as will presently appear.
  • 1 and #2 represent the amplification factor of the amplifier and balancer sections, respectively, 1'1 and r: the corresponding internal plate resistances of the respective sections, 91 and or their respective transconductances, ii and current that flows to anode 6 by virtue of the presence of source I2, and ii the current that flows to anode I by virtue of the presence of source I2. Then it will be found that and, where e is the voltage between cathode 2 and ground,
  • Equation 4 or 6 may be used for establishing the proper value for R2
  • the choice of RI involves a consideration of the fact that the voltage drop across RI contributes to the grid bias of the balancer section and the fact that the grid bias in turn affects the transconductance of that section.
  • RI may be a rheostat or other variable resistance device, and the balancing of the circuit in accordance with Equation 4 or 6 may be efiected by adjusting RI, and consequently g2, rather than by predetermining g: and then calculating the proper value for R2.
  • the voltage drop across R2 largely contributes to the grid bias of the amplifier section, and in order to limit this voltage drop to the proper value the plate current in the balancer section should not be too large.
  • a triode the lower the anode voltage the lower the plate current, but on the other hand a certain minimum voltage on anode 1 is required to secure a large transconductance.
  • An anode voltage of 60 to 80 volts has been round a good value in the case of the 6807 tube.
  • the plate resistance is efiectively the sum 01 the plate resistances of the amplifier and balancer sections.
  • the circuit parameters were as follows: RI, 0 to 1,000 ohms, adjustable; R2, 1,000 ohms; R3 500,000 ohms; battery voltage for anode 6, 225 volts; battery voltage for anode I, volts.
  • the resistance RI When the circuit is balanced the resistance RI has no net degenerative efiect on the amplification of current supplied to the input. Only resistor R2 accounts for any net degenerative effect. Where RI is an adjustable resistance it is especially easy to adjust the circuit for neutralization. From network theory it is known that changing a resistance R in a circuit by an amount AR is equivalent to placing a voltage in series with the resistance equal to iAR where i is the current flowing in R before the change. Referring to Fig. 1, the resistance RI is directly in series with the voltage V of source I2. The condition that voltage V shall have no efiect on the output, then, is that a small change in RI shall have no elIect on the output.
  • RI is simply adjusted for maximum plate current in the amplifier section.
  • the current in the last stage may be used as an indicator, and in such case RI is adjusted for maximum current if there are an odd number of stages, and for minimum current if there are an even number.
  • Fig. 2 there is illustrated schematically a two-stage amplifier, the first stage of which is designed in accordance with Fig. 1 for the neutralization of cathode drift effect and the second stage of which is a modified form in which the resistor R2 of Fig. 1 is omitted.
  • in the second stage may be the same as the device I in the first stage, having a common cathode 22, and in the amplifier section a .control grid 24 and anode 26, and in the balancer section control grid 25 and anode 21.
  • Cathode 22 is connected to ground through a single resistor R4.
  • Control grid 24 is conductively connected to anode 6 of the first stage with resistor R3 constituting an interstage coupling impedance.
  • Anode 26 is connected to one output terminal of the second stage, and through coupling resistor R5 to the positive terminal of battery H.
  • Anode 21 is connected directly to the positive terminal of battery II, and control grid 25 is connected to an intermediate tap on the batfi y.
  • a fictitious voltage source corresponding to source l2 of Fig. 1 may be assumed to be interposed in the lead to cathode 22.
  • V represent the efiective cathode drift voltage
  • e the resultant net voltage effective on the grid of the second stage.
  • Two effects contribute to the reduction of e, one being the degenerative effect of resistor R4 due to the currents from anode 26 that traverse it.
  • the other and more significant effect is due to the degenerative coupling of the balancer section through resistor R4 to the input of the stage. Even if the first effect were to be completely disregarded, the second effect alone would account for a reduction in the effect of cathode drift measured by the following equation:
  • the degeneration in the amplifier section the relation is approximately:
  • the cathode 22 is operated at a potential above CPI ground potential. S1nce this cathode may be operated at substantially the plate voltage of the first stage no separate biasing battery is required in series with grid 24. This is a subhave a serious effect on the performance of the amplifier.
  • FIG. 3 thereis shown schematically an electronic voltage regulator in accordance with the invention incorporating a circuit arrangement like that in the second stage in Fig. 2 for reducing the effect of cathode drift, and other circuit features that will appear.
  • the voltage to be regulated is represented in Fig. 3 as being the output of a full wave rectifierfilter 30 that is connected to an alternating current source to the left.
  • the regulator proper comprises in general outline a space discharge device 40 interposed in the positive side of the line and having a grid electrode for varying the voltage drop. Voltage fluctuations that tend to appear at the output terminals 60 of theregulator are caused to develop a compensating change in the potential of grid electrode and the voltage drop across discharge device 40. Regulators of this general type are discussed by Hunt and Hickman in an article, entitled On electronic voltage stabilizers, appearing in the January, 1939, issue of Review of Scientific Instruments.
  • the circuit for translating output voltage fluctuations into compensating changes in the potential of grid electrode 50 comprises discharge devices 3
  • Two opposing voltages are effective on the grid' 34 of tube 3
  • the corresponding anode 36 is connected to the positive side of the line through a resistor 53.
  • the other I anode 31 is connected directly to the positive side of the line, and its associated control electrode 35 is connected on the one hand to the positive side of the line through a high resistance 54 and to the negative side of the line through a discharge device 55 shunted by a high resistance 56.
  • Discharge device 55 is a diode having the property that the voltage drop across it is, without certain limits, independent of the current through it. It may be, for example of RCA type VR105430.
  • is connected to the negative side of the line through a resistor 51 shunted by a condenser 58. Condenser 58 has been found advantageous to reduce the tendency of the circuit to generate selfoscillations.
  • the potential of grid 35, the current through resistor 51 and the voltage drop across resistor 51 are substantially invariable, and the voltage drop is of such sense as to tendto bias grid 34 negatively with respect to cathode 32.
  • and 51, respectively may be made approximately, although not quite, equal so that grid 34 receives a fa orable negtaive bias plus potential variations corresponding to the-fluctuations in the line voltage.
  • the amplified voltage fluctuations appearing at anode 36 are applied directly to control electrode of tube 4
  • the associated anode 41 is connected directly to the positive side of the line and the common cathode 42 is connected through a resisotr 6
  • the discharge between cathode 42 and anode 41 is accordingly varied, and across resistance 6
  • This fluctuating voltage drop is applied to control electrode 44 by virtue of the connection of the latter to the junction of voltage dividing resistors 62 and G3 which are connected in series with each other across the line.
  • variable bias applied to control electrode 50 is of proper phase to compensate or oppose any voltage variation tending to appear at the output of the regulator.
  • a compensating negative bias increment would be applied to control grid 50.
  • the Fig. 3 regulator as described will reduce voltage variations appearing at the input by a factor of 2.000 or more.
  • a resistor connecting control grid 44 with the positive side of the unregulated input an additional, forward-acting effect may be obtained which tends to produce a decrease of output voltage for an increase of input voltage or vice versa.
  • resistor 65 there will be no sensible change in the output voltage for slight changes in input voltage.
  • resistor 65 it is desirable that the heaters for cathodes 32 and 42 be supplied through a. ballast lamp 59 or other accurately regulated constant current source since the feedback gain in the circuit is large enough to obscure the rectified voltage variation as compared to changes in cathode emission.
  • resistor 65 may be made variable in part and adjusted for zero or minimum hum at output terminals 60.
  • and 52 be of a highly stable type, for the regulated output voltage is equal to the product of the constant voltage across tube 55 and the quantity (R51+R52) /R5 In one instance in practice in accordance with Fig.
  • diode 55 which supplies the reference voltage, is not required to carry either a large or a fluctuating current, and it therefore may be maintained at the most favorable point on its operating characteristic.
  • tube 55 may bereplaced by a small dry cell battery, of volts for the specific example set forth, in which case resistors 54 and 56 may be omitted.
  • the battery is not required to supply any current since it simply biases grid 35, and such being the case it is capable of providing a stable source of reference voltage.
  • the regulated voltage supply shown in Fig. 3 may be employed advantageously in lieu of the battery indicated in Figs. 1 and 2, the several intermediate voltages being derived by separate sets of voltage dividing resistors connected across the output terminals of the regulator.
  • an input stage comprising a space discharge device that has a cathode, a control electrode and an output electrode, an input circuit for said stage comprising said cathode and control electrode, an output circuit for said stage comprising said output electrode, auxiliary electrode means within said discharge device and circuit means connected thereto for amplifying the effect of cathode drift associated with said cathode, and means for applying the amplified cathode drift eifect in opposing relation to cathode drift effect tending to appear in said output circuit.
  • an amplifier stage comprising a discharge device having a thermionic cathode and a set of control and output electrodes associated therewith, means comprising said set of electrodes for amplifying unidirectional current applied to said amplifier stage,
  • An amplifier stage adapted for the amplification of electric currents approximating direct current in frequency.
  • said stage comprising a discharge device having separate sets of control and output electrodes and a thermionic cathode com mon to said sets of electrodes, means for applying current to be amplified to one of said control electrodes, means for deriving the amplified current from one of said output electrodes, and means for reducing cathode drift effect in said stage comprising circuit means connected to another of said control electrodes and another of said output electrodes for deriving a cathode drift opposing voltage.
  • an amplifier stage comprising a discharge device having a pair of anodes and a common cathode, means for establishing separate and distinct space discharges between said cathode and said respective anodes, means for varying one of said discharges in accordance with current variations to be amplified, control electrode means for varying the other of said discharges in accordance with cathode drift effects associated with said common cathode, and means for reducing cathode drift effects appearing in said one discharge comprising means for subjecting said one discharge to the control of variations in said other discharge.
  • An amplifier stage comprising a discharge device having two anodes and a cathode common to said anodes, means for establishing separate space discharges between said cathode and said respective anodes, a control electrode for controlling one of said discharges, means for varying the potential of said control electrode in accordance with a quantity to be amplified, means for varying the other of said discharges in accordance with cathode drift voltages effectively in series with said common cathode, and circuit means responsive to Variations in said other discharge for neutralizing cathode drift effects tending to appear in said first discharge.
  • An amplifier stage comprising a discharge device having a first set of control grid and anode elements, a second set of control grid and anode elements, and a cathode common to said sets, means comprising said first set of elements for amplifying potentials applied to the input of said stage, said stage having an input and an output circuit each of which is grounded on one side, circuit means connecting said second control grid to said common cathode whereby the potential of said second grid is varied in accordance with the cathode drift effect associated with said cathode, and means for applying the oathode drift voltage appearing at said second anode to the input of said stage.
  • An amplifier stage comprising a device having a thermionic cathode and means including a pair of anodes and an anode voltage source therefor for maintaining two separate'discharges from 9.
  • an input stage comprising a discharge device having an ampli bomb section, a balancer section and a cathodc common to said sections, an input circuit for said amplifier section including two resistances connected in series with each other to said cathode, said balancer section comprising a control electrode and an anode, circuit means connecting said control electrode to the junction of said two resistances, and circuit means connecting said anode to said cathode through said two resistances.
  • one of said resistances is of such magnitude that a cathode drift neutralizing voltage is established in said input circuit.
  • an input stage comprising a discharge device having two sets of electrically separate electrodes and a common cathode, means comprising one of said sets of electrodes for amplifying currents applied to the input of said stage, means comprising the other of said sets of electrodes for amplifying cathode drift effects associated with said common cathode, and means for degeneratively applying to the input of said stage the amplified cathode drift effects from said other set of electrodes.
  • the method of compensating for the efiect of cathode drift in the amplification of direct and low frequency electric variables which comprises separately amplifying the effective cathode drift voltage and applying it as so amplified to the neutralization of cathode drift effect tending to appearin the amplified variable.
  • the method which comprises concurrently amplifying the effective cathode drift voltage and a variable to be amplified, separately translating the said effective cathode drift voltage with substantial discrimination against any component of the said variable that may be present, and applying the separately translated cathode drift voltage in neutralizing relation to the cathode drift effect tending to appear as a result of the aforesaid concurrent amplification of the effective cathode drift voltage and the variable to be amplified.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Automation & Control Theory (AREA)
  • Amplifiers (AREA)
US391376A 1941-05-01 1941-05-01 Electric wave translation Expired - Lifetime US2308997A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL67373D NL67373C (enrdf_load_stackoverflow) 1941-05-01
US391376A US2308997A (en) 1941-05-01 1941-05-01 Electric wave translation
FR948178D FR948178A (fr) 1941-05-01 1947-06-18 Dispositif d'amplification des ondes électriques
GB20137/47A GB625379A (en) 1941-05-01 1947-07-25 Improvements in electric discharge tube amplifiers

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FR (1) FR948178A (enrdf_load_stackoverflow)
GB (1) GB625379A (enrdf_load_stackoverflow)
NL (1) NL67373C (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2470048A (en) * 1946-05-31 1949-05-10 Bendix Aviat Corp Television receiver
US2480418A (en) * 1944-05-04 1949-08-30 Radio Television Inst Inc Amplifier with heater compensation
US2511122A (en) * 1945-06-13 1950-06-13 Bell Telephone Labor Inc Amplifier compensated for cathode emission change
US2523468A (en) * 1945-01-25 1950-09-26 Donald G C Hare Emission stabilized electronic valve
US2547107A (en) * 1947-09-18 1951-04-03 Bell Telephone Labor Inc Stabilized amplifier
US2601485A (en) * 1948-11-27 1952-06-24 Sun Oil Co Circuit having high input impedance and linear response
US2786197A (en) * 1946-03-29 1957-03-19 Sperry Rand Corp Ranging system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2480418A (en) * 1944-05-04 1949-08-30 Radio Television Inst Inc Amplifier with heater compensation
US2523468A (en) * 1945-01-25 1950-09-26 Donald G C Hare Emission stabilized electronic valve
US2511122A (en) * 1945-06-13 1950-06-13 Bell Telephone Labor Inc Amplifier compensated for cathode emission change
US2786197A (en) * 1946-03-29 1957-03-19 Sperry Rand Corp Ranging system
US2470048A (en) * 1946-05-31 1949-05-10 Bendix Aviat Corp Television receiver
US2547107A (en) * 1947-09-18 1951-04-03 Bell Telephone Labor Inc Stabilized amplifier
US2601485A (en) * 1948-11-27 1952-06-24 Sun Oil Co Circuit having high input impedance and linear response

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GB625379A (en) 1949-06-27
FR948178A (fr) 1949-07-25
NL67373C (enrdf_load_stackoverflow)

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