Patent US3689824A successfully refreshed from Google Patents.
US3689824A
Expired / Lapsed
US
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Circuit for conversion from (rms) a.c. to d.c.
Assignee: Guildline Instruments Ltd
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Filing: 1971-08-30
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Granted: 1972-09-05
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Expires: 1991-08-30
Abstract
Abstract A multijunction thermal convertor of the differential type is employed to obtain energy balance between a D.C. input voltage and an A.C. input voltage in order to determine the RMS value of the A.C. voltage. Amplified feedback from the output of the convertor is used to maintain this balance, by controlling the gain of an amplifier in the A.C. input. The value of this gain in relation to the D.C. input voltage is a measure of the desired (RMS) A.C. input voltage, and such value is expressed as a D.C. output voltage. The system has greater accuracy than previous systems for achieving a similar measurement.
Inventors
- 👤 Ian Malcolm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:16
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/02; G01R19/03; G01R1/00; G01R1/28
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
184 words
A circuit for conversion of an (RMS) A.C. input voltage to a corresponding D.C. output voltage, comprising: a. a convertor having a D.C. input, an A.C. input, and an output representative of a difference between a D.C. voltage applied to said D.C. input and the RMS value of an A.C. voltage applied to said A.C. input, b. means or connecting said D.C. input to a D.C. reference voltage, c. amplifier means including variable gain control means, d. means connecting the output of said amplifier means to said A.C. input of the convertor, e. means for connecting an input of said amplifier means to the A.C. input voltage to be converted, f. means connecting said output of the convertor to said gain control means to vary the same to bring said convertor output to zero, and g. means for determining the ratio between the gain of said gain control means and the value of said D.C. reference voltage including means for expressing said ratio as a D.C. output voltage to provide a measure of the RMS value of said A.C. input voltage to be converted.
Claim 2
Dependent Claim
184 words
A circuit for conversion of an (RMS) A.C. input voltage to a corresponding D.C. output voltage, comprising: a. a convertor having a D.C. input, an A.C. input, and an output representative of a difference between a D.C. voltage applied to said D.C. input and the RMS value of an A.C. voltage applied to said A.C. input, b. means or connecting said D.C. input to a D.C. reference voltage, c. amplifier means including variable gain control means, d. means connecting the output of said amplifier means to said A.C. input of the convertor, e. means for connecting an input of said amplifier means to the A.C. input voltage to be converted, f. means connecting said output of the convertor to said gain control means to vary the same to bring said convertor output to zero, and g. means for determining the ratio between the gain of said gain control means and the value of said D.C. reference voltage including means for expressing said ratio as a D.C. output voltage to provide a measure of the RMS value of said A.C. input voltage to be converted.
Claim 3
Dependent Claim
27 words
A circuit according to claim 1, wherein said means (g) comprise a feed-back loop for determining said gain as a value independent of said D.C. reference voltage.
Claim 4
Dependent Claim
278 words
A circuit for conversion of an (RMS) A.C. input voltage to a corresponding D.C. output voltage, comprising: a. a convertor having a D.C. input, and A.C. input, and an output representative of a difference between a D.C. voltage applied to said D.C. input and the RMS value of an A.C. voltage applied to said A.C. input, b. means for connecting said D.C. input to a D.C. reference voltage, c. a first amplifier including variable gain control means and having equal A.C. and D.C. gain, d. means for connecting an input of said amplifier to the A.C. input voltage to be converted, e. a high gain D.C. amplifier including means for connecting a first input thereof to said D.C. reference voltage, means connecting the output thereof to an input of said first amplifier, and means connecting the output of said first amplifier to a second input of said high gain amplifier, said first and second inputs of the high gain amplifier being of opposite polarity, f. a further amplifier of predetermined gain, including means connecting a first input thereof to the output of said first amplifier, means connecting the output thereof to said A.C. input of the convertor, and means for connecting a second input thereof to said D.C. reference voLtage, said first and second inputs of the further amplifier being of opposite polarity, g. and means connecting said output of the convertor to said gain control means to control the same to bring said convertor output to zero and hence cause the output of said high gain D.C. amplifier to provide a D.C. output voltage proportional to the RMS value of said A.C. input voltage to be converted.
Claim 5
Dependent Claim
278 words
A circuit for conversion of an (RMS) A.C. input voltage to a corresponding D.C. output voltage, comprising: a. a convertor having a D.C. input, and A.C. input, and an output representative of a difference between a D.C. voltage applied to said D.C. input and the RMS value of an A.C. voltage applied to said A.C. input, b. means for connecting said D.C. input to a D.C. reference voltage, c. a first amplifier including variable gain control means and having equal A.C. and D.C. gain, d. means for connecting an input of said amplifier to the A.C. input voltage to be converted, e. a high gain D.C. amplifier including means for connecting a first input thereof to said D.C. reference voltage, means connecting the output thereof to an input of said first amplifier, and means connecting the output of said first amplifier to a second input of said high gain amplifier, said first and second inputs of the high gain amplifier being of opposite polarity, f. a further amplifier of predetermined gain, including means connecting a first input thereof to the output of said first amplifier, means connecting the output thereof to said A.C. input of the convertor, and means for connecting a second input thereof to said D.C. reference voLtage, said first and second inputs of the further amplifier being of opposite polarity, g. and means connecting said output of the convertor to said gain control means to control the same to bring said convertor output to zero and hence cause the output of said high gain D.C. amplifier to provide a D.C. output voltage proportional to the RMS value of said A.C. input voltage to be converted.
Claim 6
Dependent Claim
35 words
A circuit according to claim 3, wherein the gain of said further amplifier is unity, whereby said D.C. output voltage is numerically equivalent to the RMS value of said A.C. input voltage to be converted.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |