US3584296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impedance bridge apparatus having lead wire resistance compensation means
Assignee: AUTOMATIC SYSTEMS LAB Ltd
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Filing: 1968-11-07
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Granted: 1971-06-08
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Expires: 1988-11-07
Abstract
Abstract A bridge circuit for the comparison of the values of electrical impedances. The novel feature is that an additional source of electrical energy is provided which is connected into the bridge circuit in such a way as to ensure that the current through or the voltage across the impedances are in a predetermined ratio. This prevents for example, the resistances of the lead wires affecting the accuracy of the bridge.
Inventors
- 👤 Peter Caleb Frederi Wolfendale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:52
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/16; G01R27/08; G01R27/10; G01R27/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
231 words
Apparatus for measuring the ratio between first and second eLectrical impedances, comprising: means including a first voltage source (1) and first leads of finite resistance for energizing said impedances in series; reference voltage divider means (6) connected across the remote ends of said first and second impedances, said voltage divider means including adjustable taps; second lead means connecting tapped portions of said voltage divider means in parallel across said first and second impedances, respectively; first detector means (4) and (4a) connected in said second lead means for indicating when the divider taps are adjusted to cause tapped portions of said voltage divider means to bear a predetermined ratio to the ratio of the voltages across the first and second impedances, respectively; second detector means (9) connected between one of said remote ends of said first and second impedance and a remote end of said reference voltage divider means for indicating the total degree of unbalance of said voltage divider means relative to said first and second impedance means; and control means including a second voltage source (7) connected across said voltage divider means and operable by said second detector means for maintaining the voltages across said first and second impedances in a predetermined ratio, whereby the effect of the leads on the electrical measurement is eliminated, and a true indication of the ratio of said first and second impedances is presented.
Claim 2
Dependent Claim
231 words
Apparatus for measuring the ratio between first and second eLectrical impedances, comprising: means including a first voltage source (1) and first leads of finite resistance for energizing said impedances in series; reference voltage divider means (6) connected across the remote ends of said first and second impedances, said voltage divider means including adjustable taps; second lead means connecting tapped portions of said voltage divider means in parallel across said first and second impedances, respectively; first detector means (4) and (4a) connected in said second lead means for indicating when the divider taps are adjusted to cause tapped portions of said voltage divider means to bear a predetermined ratio to the ratio of the voltages across the first and second impedances, respectively; second detector means (9) connected between one of said remote ends of said first and second impedance and a remote end of said reference voltage divider means for indicating the total degree of unbalance of said voltage divider means relative to said first and second impedance means; and control means including a second voltage source (7) connected across said voltage divider means and operable by said second detector means for maintaining the voltages across said first and second impedances in a predetermined ratio, whereby the effect of the leads on the electrical measurement is eliminated, and a true indication of the ratio of said first and second impedances is presented.
Claim 3
Dependent Claim
38 words
Apparatus as defined in claim 1, wherein said second detector means is connected in a lead between one end of said voltage divider branch and one end of the series branch that includes said first and second impedances.
Claim 4
Dependent Claim
77 words
Apparatus as defined in claim 2, wherein said first detector means includes a first detector (4) connected in a first lead of said second lead means between one tap of said potential divider means and that end of said first impedance that is adjacent said second impedance, and another detector (4a) connected in a second lead of said second lead means between another tap and that end of said second impedance that is adjacent said first impedance.
Claim 5
Dependent Claim
33 words
Apparatus as defined in claim 2, wherein said control means includes voltage attenuating means, and servo means for controlling said attenuating means as a function of the output of said second detecting means.
Claim 6
Dependent Claim
118 words
A circuit arrangement according to claim 1 comprising a first AC generator for supplying an electrical current to two pairs of terminals connected in series for said first and second impedances respectively, a first detecting means connected in series with a first primary winding of a transformer connected across one pair of terminals, a second detecting means connected in series with a second primary winding of said transformer connected across the other pair of terminals, said first primary winding being provided with means for varying the number of turns therein, a second AC generator connected to the secondary of said transformer and means controlled by said second detecting means for controlling the relative values of the two generators.
Claim 7
Dependent Claim
112 words
A circuit arrangement according to claim 1 comprising a first pair of terminals for said first impedance, a second pair of terminals for said second impedance, a first generator connected across one terminal of each pair, a second generator connected across the other terminals of each pair, a potentiometer connected across said first generator, a first detecting means connected from one terminal of said second generator to a first variable tap on said potentiometer, a second detecting means connected from the other terminal of said second generator to a second variable tap on said potentiometer, and means controlled by said second detecting means for controlling the relative values of the two generators.
Claim 8
Dependent Claim
137 words
A circuit arrangement according to claim 1 comprising a first AC generator means adapted to supply electrical current via the first primary winding of a transformer to a first pair of terminaLs for said first impedance, a second AC generator means adapted to supply electrical current via a second primary winding of said transformer to a second pair of terminals for said second impedance, a conductor connecting one of each of the pairs of terminals, a potentiometer connected across said second pair of terminals, a first detecting means connected from the other terminal of said first pair of terminals to the variable tap of said potentiometer, a second detecting means connected to the secondary of said transformer, and means controlled by the output of said second detecting means for controlling the relative values of the two generators.
Claim 9
Dependent Claim
153 words
A circuit arrangement according to claim 1 comprising a DC generator for supplying an electrical current to two pairs of terminals connected in series for said first and second impedances respectively, in a path across said first pair of terminals a vibrating switch for connecting the voltage across said pair of terminals effectively to AC, a first detecting means in series with a first primary winding of a transformer, in a path across said second pair of terminals, a vibrating switch for connecting the voltage across said pair of terminals effectively to AC, a second detecting means connected in series with a second primary winding of said transformer, said first primary winding being provided with means for varying the number of turns therein, said generator being connected via a vibrating switch to convert its output effectively to AC and an attenuator controlled by said second detecting means to the secondary of said transformer.
References Cited (Backward Citations)
US1465352A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |