US5132610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digitizing power meter
Assignee: Prodigit Electronics Co Ltd
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Filing: 1990-02-07
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Granted: 1992-07-21
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Expires: 2010-02-07
Abstract
Abstract A digitizing power meter for measuring voltage and current's root-mean-square, average power and power factor, which includes a voltage detector circuit and a current detector circuit to measure voltage and current analog signal; a phase-lock circuit, a voltage Sampling/Holding circuit, a current Sampling/Holding circuit, a trigger circuit, a voltage A/D converter and a current A/D converter to convert analog signal to measure to digital signal; and a digital processing circuit to accurately measure out voltage and current's root-mean-square, average power and power factor by means of the operation of its microprocessor.
Inventors
- 👤 Liu Ying-Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:02
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/133
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
235 words
A digitizing power meter for measuring voltage root mean square, average power, and power factor of an analog signal, comprising: a first circuit system for converting the voltage component of an input analog signal into a first digital signal, said first circuit system including a voltage amplifier (1), a voltage sampling/holding circuit (3), and a voltage A/D converter (4); a second circuit system for converting the current component of the input analog signal into a second digital signal, said second circuit system including an ampere amplifier (8), a current sampling/holding circuit (10), and a current A/D converter 11; a signal detector means (5) connected to said voltage amplifier and to said ampere amplifier for producing a square wave signal; a phase lock circuit (6) connected to said signal detector means for changing the frequency of the square wave signal; a trigger circuit (7) having its input connected to the output of the phase lock circuit for developing a timing signal; said trigger circuit having separate outputs connected to said voltage sampling/holding circuit, said current sampling/holding circuit, said voltage A/D converter, and said current A/D converter for delivering timing signals thereto; a digital signal processing circuit comprising a microprocessor (18) and a RAM (17), and a photo isolator (19) having a first side thereof connected to said digital signal processing circuit, and a second side thereof connected to said trigger circuit and to said A/D converters.
Claim 2
Dependent Claim
235 words
A digitizing power meter for measuring voltage root mean square, average power, and power factor of an analog signal, comprising: a first circuit system for converting the voltage component of an input analog signal into a first digital signal, said first circuit system including a voltage amplifier (1), a voltage sampling/holding circuit (3), and a voltage A/D converter (4); a second circuit system for converting the current component of the input analog signal into a second digital signal, said second circuit system including an ampere amplifier (8), a current sampling/holding circuit (10), and a current A/D converter 11; a signal detector means (5) connected to said voltage amplifier and to said ampere amplifier for producing a square wave signal; a phase lock circuit (6) connected to said signal detector means for changing the frequency of the square wave signal; a trigger circuit (7) having its input connected to the output of the phase lock circuit for developing a timing signal; said trigger circuit having separate outputs connected to said voltage sampling/holding circuit, said current sampling/holding circuit, said voltage A/D converter, and said current A/D converter for delivering timing signals thereto; a digital signal processing circuit comprising a microprocessor (18) and a RAM (17), and a photo isolator (19) having a first side thereof connected to said digital signal processing circuit, and a second side thereof connected to said trigger circuit and to said A/D converters.
Claim 3
Dependent Claim
62 words
The digitizing power meter of claim 1, wherein said voltage sampling/holding circuit (3) comprises an operational amplifier (407), a first photo-coupler (405) for delivering an input signal to one input terminal of said operational amplifier, and a second photo-coupler (414) connected to the output of said amplifier (407) for delivering a reference signal to a second input terminal of said operational amplifier.
References Cited (Backward Citations)
US4217545A
Cited
US4126825A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-21 | 1996-01-20 | 1996-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-21 | 2000-01-20 | 2000-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-21 | 2004-01-20 | 2004-07-21 | $7700.00 | Window Closed / Lapsed |