Patent US3811073A successfully refreshed from Google Patents.
US3811073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alternating current sensing circuit and method
Assignee: Westinghouse Electric Corp
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Filing: 1973-03-05
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Granted: 1974-05-14
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Expires: 1993-03-05
Abstract
Abstract A full wave rectified voltage that is proportional to alternating current in a load circuit is developed by using inverse parallel switching devices having a rectifying characteristic, such as thyristors, to develop half wave rectified signals processed by an operational amplifier to produce the desired signal that is useful for purposes such as the input to an inverse time delay circuit.
Inventors
- 👤 K Shuey
- 👤 D Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:29
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
180 words
Electronic apparatus, for producing a rectified voltage proportional to an alternating current, comprising: an alternating voltage source, a load, and switching means for selectively permitting current flow in a closed circuit loop; said switching means comprising first and second solid state switching devices that have a rectifying characteristic and which are connected in an inverse parallel combination with a first pair of oppositely poled terminals connected in said loop, first and second resistive elements having first terminals respectively connected in series with said first and second switching devices at a second pair of oppositely poled terminals, said first and second resistive elements having a common connection in said loop; an operational amplifier having a pair of input terminals connected respectively through third and fourth resistive elements to said first terminals of said first and second resistive elements; and a fifth resistive element connected from one of said input terminals to an output terminal, said operational amplifier and said resistive elements as so connected being operative to produce a full wave rectified voltage waveform representing the alternating current of said loop.
Claim 2
Dependent Claim
180 words
Electronic apparatus, for producing a rectified voltage proportional to an alternating current, comprising: an alternating voltage source, a load, and switching means for selectively permitting current flow in a closed circuit loop; said switching means comprising first and second solid state switching devices that have a rectifying characteristic and which are connected in an inverse parallel combination with a first pair of oppositely poled terminals connected in said loop, first and second resistive elements having first terminals respectively connected in series with said first and second switching devices at a second pair of oppositely poled terminals, said first and second resistive elements having a common connection in said loop; an operational amplifier having a pair of input terminals connected respectively through third and fourth resistive elements to said first terminals of said first and second resistive elements; and a fifth resistive element connected from one of said input terminals to an output terminal, said operational amplifier and said resistive elements as so connected being operative to produce a full wave rectified voltage waveform representing the alternating current of said loop.
Claim 3
Dependent Claim
14 words
The subject matter of claim 1 wherein: said solid state switching devices are thyristors.
Claim 4
Dependent Claim
42 words
The subject matter of claim 2 wherein: the output of said operational amplifier is supplied to an inverse time delay trip circuit operatively associated with said thyristors to interrupt current flow in said loop upon occurrence of a predetermined overload current flow.
Claim 5
Dependent Claim
119 words
In combination: a pair of semiconductor switching devices having an inverse parallel relation therebetween for power control between an alternating voltage source and a load, said switching devices having a rectifying characteristic; resistive means for producing individual half wave rectified voltage signals representing the positive and negative polarity half-cycles of the AC waveform in the load circuit as rectified by said switching devices, said resistive means comprising resistive elements respectively in series with said switching devices within said inverse parallel combination; means for inverting one of said half wave rectified signals for making both said half wave rectified signals of the same polarity and for combining said two half wave rectified signals to produce a full wave rectified signal.
Claim 6
Dependent Claim
119 words
In combination: a pair of semiconductor switching devices having an inverse parallel relation therebetween for power control between an alternating voltage source and a load, said switching devices having a rectifying characteristic; resistive means for producing individual half wave rectified voltage signals representing the positive and negative polarity half-cycles of the AC waveform in the load circuit as rectified by said switching devices, said resistive means comprising resistive elements respectively in series with said switching devices within said inverse parallel combination; means for inverting one of said half wave rectified signals for making both said half wave rectified signals of the same polarity and for combining said two half wave rectified signals to produce a full wave rectified signal.
Claim 7
Dependent Claim
18 words
The subject matter of claim 4 wherein: said means for inverting and combining comprises a single operational amplifier.
Claim 8
Dependent Claim
65 words
The subject matter of claim 5 wherein: said operational amplifier has a pair of input terminals resistively connected to points between said thyristors and their respective series resistive elements, the signal applied to a first of said input terminals being inverted in polarity by said operational amplifier; and an additional resistor is connected between the output of said operational amplifier and said first input terminal.
References Cited (Backward Citations)
US3408558A
Cited
US3602773A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |