GB620140A - Improvements relating to d.c. amplifiers - Google Patents

Improvements relating to d.c. amplifiers

Info

Publication number
GB620140A
GB620140A GB865846A GB865846A GB620140A GB 620140 A GB620140 A GB 620140A GB 865846 A GB865846 A GB 865846A GB 865846 A GB865846 A GB 865846A GB 620140 A GB620140 A GB 620140A
Authority
GB
United Kingdom
Prior art keywords
amplifier
s1
voltage
c2
opens
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
Application number
GB865846A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
British Thomson-Houston Co Ltd
Original Assignee
British Thomson-Houston Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by British Thomson-Houston Co Ltd filed Critical British Thomson-Houston Co Ltd
Priority to GB865846A priority Critical patent/GB620140A/en
Publication of GB620140A publication Critical patent/GB620140A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/34Dc amplifiers in which all stages are dc-coupled
    • H03F3/36Dc amplifiers in which all stages are dc-coupled with tubes only

Abstract

620,140. Valve amplifying circuits. BRITISH THOMSON-HOUSTON CO., Ltd., and OWEN, C.E. March 20, 1946, No. 8658. [Class 40 (vi)] Zero drift in a D.C. amplifier is reduced by associating a series condenser with the input of the amplifier which is charged from the output of the amplifier to a potential which is substantially equal to but of opposite polarity to a voltage representative of the zero drift in the amplifier. In the D.C. amplifier, Fig. 1, when switch S1 is closed, a correction voltage is fed back to charge condenser C1 via a switch S2 which closes at approximately the same time as S1 but opens just before S1 opens, the resistor R3 enables the amplifier to function in the event of a failure of the switches. A modification, Fig. 3 (not shown), enables improved correction to be obtained by applying the correction to a D.C. amplifier having an overall negative feedback. Fig. 5 shows an arrangement to prevent the output of the amplifier falling away during the period when the input is shorted by charging a condenser C2 via switch S3, so that during the period when switch S1 is closed, S3 is opened to isolate C2 from the output of the amplifier. S3 opens just before S1 closes and closes just after S1 opens. An isolating amplifier is as shown provided between the condenser C2 and the output and negative feed-back is preferably taken from the output of the final stage to the input circuit of the amplifier. Fig. 8 shows the first stages VI, V2 of a D.C. amplifier, a voltage being obtained at a point D which bears a substantially constant relationship to the zero drift voltage of the amplifier. The voltage at D is fed via contact S which opens and closes periodically to a corrector unit, the output stage V5 of which feeds condensers C1 and C2 through two reversely-connected diodes V6 and V7, so biassed as to prevent any charge on Cl leaking away. The correction amplifier gain is of such a value that a change in voltage at the anode of V5 is produced equal to or greater than the bias on either diode when S1 is closed and the zero drift error in the D.C. amplifier is the largest that can be tolerated. Condenser C3 charges to a potential proportional to the zero error when S1 opens, when S1 closes C3 is discharged by R10 and either V6 or V7 conducts, depending on the sign of the zero error voltage and a voltage developed across R11 is applied as negative feed-back to the input of the corrector amplifier, the charge acquired by C1 is substantially proportional to that lost by C3, hence the voltage rise of Cl is proportional to the residual zero error of the D.C. amplifier. C2 charges from C when S opens and by choosing suitable values of C1, C2, R10 and R11, the change in potential of C2 due to an operation of S1, is made substantially equal to the residual zero error of the amplifier before S1 operates. As the zero drifts a correction is put in at each operation of switch S1; the combination of R9 with C4 and R8 with C2 smooths out the corrections to obviate sudden changes in the output level. One corrector unit may be used to compensate for the zero drift errors in a number of D.C. amplifiers. The corrector unit being switched from one amplifier to the next by rotary switches, Fig. 9 (not shown).
GB865846A 1946-03-20 1946-03-20 Improvements relating to d.c. amplifiers Expired GB620140A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB865846A GB620140A (en) 1946-03-20 1946-03-20 Improvements relating to d.c. amplifiers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB865846A GB620140A (en) 1946-03-20 1946-03-20 Improvements relating to d.c. amplifiers

Publications (1)

Publication Number Publication Date
GB620140A true GB620140A (en) 1949-03-21

Family

ID=9856728

Family Applications (1)

Application Number Title Priority Date Filing Date
GB865846A Expired GB620140A (en) 1946-03-20 1946-03-20 Improvements relating to d.c. amplifiers

Country Status (1)

Country Link
GB (1) GB620140A (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2730573A (en) * 1948-12-01 1956-01-10 Sperry Gyroscope Co Ltd Feed-back amplifier systems and servo mechanisms that are adapted to respond to input changes at very low frequencies
US2734949A (en) * 1956-02-14 berry
US2768247A (en) * 1952-04-22 1956-10-23 Socony Mobil Oil Co Inc Stabilized low frequency amplifier with drift correction
US2795653A (en) * 1953-11-12 1957-06-11 Reeves Instrument Corp Vacuum tube voltmeter amplifier circuit
US2801296A (en) * 1954-02-09 1957-07-30 Bell Telephone Labor Inc D.-c. summing amplifier drift correction
US2807677A (en) * 1951-03-01 1957-09-24 Dow Chemical Co Stable direct-current amplifier
US2829268A (en) * 1952-05-05 1958-04-01 Industrial Nucleonics Corp Standardization system
US2846522A (en) * 1953-02-18 1958-08-05 Sun Oil Co Differential amplifier circuits
US2866018A (en) * 1956-08-13 1958-12-23 Cons Electrodynamics Corp Direct current differential amplifying system
US2874235A (en) * 1955-09-28 1959-02-17 Edward C Hartwig Ultra-stabilized d. c. amplifier
US2895006A (en) * 1952-08-28 1959-07-14 Eastman Kodak Co Apparatus for balancing scanning systems
US2896027A (en) * 1953-10-19 1959-07-21 Melpar Inc Reflex amplifiers
US2919409A (en) * 1951-10-22 1959-12-29 Leeds & Northrup Co System for adjusting amplifiers
US2934709A (en) * 1954-09-22 1960-04-26 Leeds & Northrup Co High-fidelity wide-band amplifier
US2954529A (en) * 1956-06-04 1960-09-27 Franklin F Offner Arrangement for inhibiting drift in amplifiers
US2965852A (en) * 1954-10-25 1960-12-20 Texas Instruments Inc Cathode follower
US2970266A (en) * 1957-01-22 1961-01-31 Beckman Instruments Inc Self-zeroing amplifier
US3147446A (en) * 1960-04-21 1964-09-01 Dynamics Corp America Stabilized drift compensated direct current amplifier
US3768028A (en) * 1972-03-22 1973-10-23 Optimation Inc A.c.-d.c. amplifier system
US3825854A (en) * 1970-12-10 1974-07-23 Honeywell Inf Systems Amplifier with substantially zero distortion products

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734949A (en) * 1956-02-14 berry
US2730573A (en) * 1948-12-01 1956-01-10 Sperry Gyroscope Co Ltd Feed-back amplifier systems and servo mechanisms that are adapted to respond to input changes at very low frequencies
US2807677A (en) * 1951-03-01 1957-09-24 Dow Chemical Co Stable direct-current amplifier
US2919409A (en) * 1951-10-22 1959-12-29 Leeds & Northrup Co System for adjusting amplifiers
US2768247A (en) * 1952-04-22 1956-10-23 Socony Mobil Oil Co Inc Stabilized low frequency amplifier with drift correction
US2829268A (en) * 1952-05-05 1958-04-01 Industrial Nucleonics Corp Standardization system
US2895006A (en) * 1952-08-28 1959-07-14 Eastman Kodak Co Apparatus for balancing scanning systems
US2846522A (en) * 1953-02-18 1958-08-05 Sun Oil Co Differential amplifier circuits
US2896027A (en) * 1953-10-19 1959-07-21 Melpar Inc Reflex amplifiers
US2795653A (en) * 1953-11-12 1957-06-11 Reeves Instrument Corp Vacuum tube voltmeter amplifier circuit
US2801296A (en) * 1954-02-09 1957-07-30 Bell Telephone Labor Inc D.-c. summing amplifier drift correction
US2934709A (en) * 1954-09-22 1960-04-26 Leeds & Northrup Co High-fidelity wide-band amplifier
US2965852A (en) * 1954-10-25 1960-12-20 Texas Instruments Inc Cathode follower
US2874235A (en) * 1955-09-28 1959-02-17 Edward C Hartwig Ultra-stabilized d. c. amplifier
US2954529A (en) * 1956-06-04 1960-09-27 Franklin F Offner Arrangement for inhibiting drift in amplifiers
US2866018A (en) * 1956-08-13 1958-12-23 Cons Electrodynamics Corp Direct current differential amplifying system
US2970266A (en) * 1957-01-22 1961-01-31 Beckman Instruments Inc Self-zeroing amplifier
DE1113008B (en) * 1957-01-22 1961-08-24 Beckman Instruments Inc Coupled against Gleichspannungsverstaerker with drift compensation
US3147446A (en) * 1960-04-21 1964-09-01 Dynamics Corp America Stabilized drift compensated direct current amplifier
US3825854A (en) * 1970-12-10 1974-07-23 Honeywell Inf Systems Amplifier with substantially zero distortion products
US3768028A (en) * 1972-03-22 1973-10-23 Optimation Inc A.c.-d.c. amplifier system

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