Patent US4027239A successfully refreshed from Google Patents.
US4027239A
Expired / Lapsed
US
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Current level detector
Assignee: Energy Research and Development Administration ERDA
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Filing: 1975-11-25
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Granted: 1977-05-31
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Expires: 1995-11-25
Abstract
Abstract A device is provided for detecting the current level of a DC signal. It includes an even harmonic modulator to which a reference AC signal is applied. The unknown DC signal acts on the reference AC signal so that the output of the modulator includes an even harmonic whose amplitude is proportional to the unknown DC current.
Inventors
- 👤 Cordon R. Kerns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:08
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
195 words
A device for detecting the current level of a DC signal, comprising: reference signal means for developing an AC reference signal of particular frequency; a balanced push-pull type input circuit coupled to said reference signal means and having said AC reference signal applied thereto, two front-to-back coupled diode pairs with said diode pairs coupled in series with each other and with said balanced input circuit, a first DC input connector coupled to said balanced input circuit, a second DC input connector, an output junction directly coupling the two diode pairs, output means coupled between the second DC input connector and the output junction, the DC current signal being applied as an offset so that with current level of the DC signal nonzero there is developed at the output junction an output signal composed of even harmonic frequencies of said particular frequency with the phase of said output determined by the polarity of said DC signal with the amplitude of said output proportional to the amplitude of said DC signal, and a demodulator coupled to said diode pairs responsive to said output signal to develop a monitor signal indicating the current level of the DC signal.
Claim 2
Independent Claim
195 words
A device for detecting the current level of a DC signal, comprising: reference signal means for developing an AC reference signal of particular frequency; a balanced push-pull type input circuit coupled to said reference signal means and having said AC reference signal applied thereto, two front-to-back coupled diode pairs with said diode pairs coupled in series with each other and with said balanced input circuit, a first DC input connector coupled to said balanced input circuit, a second DC input connector, an output junction directly coupling the two diode pairs, output means coupled between the second DC input connector and the output junction, the DC current signal being applied as an offset so that with current level of the DC signal nonzero there is developed at the output junction an output signal composed of even harmonic frequencies of said particular frequency with the phase of said output determined by the polarity of said DC signal with the amplitude of said output proportional to the amplitude of said DC signal, and a demodulator coupled to said diode pairs responsive to said output signal to develop a monitor signal indicating the current level of the DC signal.
Claim 3
Dependent Claim
75 words
The device of claim 1 wherein said balanced input circuit includes a transformer having a center tap on the secondary winding thereof, said transformer having said AC reference signal applied to the primary winding thereof and having one end of the secondary winding thereof coupled to one diode pair and the other end of the secondary winding thereof coupled to the other diode pair, the first DC input connector being connected to said center tap.
Claim 4
Dependent Claim
32 words
The device of claim 2 wherein said demodulator includes means for selecting the second harmonic of said particular frequency, said demodulator being responsive to said second harmonic to develop said monitor signal.
Claim 5
Dependent Claim
52 words
The device of claim 3 wherein said demodulator includes a synchronous detector coupled to said reference signal means and being responsive to said second harmonic and said AC reference signal to develop said monitor signal being proportional to the amplitude of and of polarity determined by the direction of the DC signal.
Claim 6
Dependent Claim
26 words
The device of claim 4 further including a bypass comprised of a third pair of front-to-back coupled diodes coupled in parallel across the other diode pairs.
Claim 7
Dependent Claim
36 words
The device of claim 5 wherein said synchronous detector includes a threshold adjust for establishing a particular threshold value, said synchronous detector developing an alarm signal with said monitor signal in excess of said threshold value.
Claim 8
Dependent Claim
25 words
The device of claim 6 further including display means coupled to said synchronous detector and being responsive to said monitor to display the value thereof.
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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |