US4733173A
Expired / Lapsed
US
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Electronic component measurement apparatus
Assignee: HP Inc
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Filing: 1985-10-30
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Granted: 1988-03-22
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Expires: 2005-10-30
Abstract
Abstract Apparatus for measuring the A.C. characteristics of a circuit element under test maintains a stable D.C. bias voltage across the component under test by sensing the difference between the output voltage of the D.C. bias voltage source and the voltage drop across the circuit element under test, to control the D.C. bias voltage applied and to compensate for variable voltage drops in the measurement circuit. The apparatus compensates both for the fixed resistance in the circuit and for the variable resistance due to changing the range resistor.
Inventors
- 👤 Heinz-Gunter Bach
- 👤 Wolfgang Dressler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:54
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
153 words
Apparatus for measuring A.C. characteristics of a component to which superimposed A.C. signals and D.C. bias voltages are applied, in a measurement circuit having a variable range resistor, comprising: an A.C. signal source connected to the component under test for providing the A.C. signal across the component; a D.C. variable voltage source connected with the A.C. signal source for providing a selected D.C. bias voltage superimposed on the A.C. signal; means for detecting the D.C. voltage drop across the component under test; control means including an operational amplifier with high gain for comparing the D.C. voltage drop across the component under test with the output voltage of the D.C. variable voltage source to control the applied D.C. voltage to maintain the D.C. voltage drop across the component under test substantially equal to the output voltage of the D.C. variable voltage source; and means for measuring the A.C. characteristics of the component under test.
Claim 2
Dependent Claim
153 words
Apparatus for measuring A.C. characteristics of a component to which superimposed A.C. signals and D.C. bias voltages are applied, in a measurement circuit having a variable range resistor, comprising: an A.C. signal source connected to the component under test for providing the A.C. signal across the component; a D.C. variable voltage source connected with the A.C. signal source for providing a selected D.C. bias voltage superimposed on the A.C. signal; means for detecting the D.C. voltage drop across the component under test; control means including an operational amplifier with high gain for comparing the D.C. voltage drop across the component under test with the output voltage of the D.C. variable voltage source to control the applied D.C. voltage to maintain the D.C. voltage drop across the component under test substantially equal to the output voltage of the D.C. variable voltage source; and means for measuring the A.C. characteristics of the component under test.
Claim 3
Dependent Claim
54 words
Measurement apparatus as in claim 1 wherein the means for detecting the D.C. voltage drop across the compponent under test comprises an amplifier having unity gain, and having an inverting input connected to one side of the component under test and a noninverting input connected to the other side of the component under test.
References Cited (Backward Citations)
DE224956C
Cited
SU473131A1
Cited
JPS5717032A
Cited
SU970263A1
Cited
US4438498A
Cited
JPS59119283A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-22 | 1991-09-21 | 1992-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-22 | 1995-09-21 | 1996-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-22 | 1999-09-21 | 2000-03-22 | $7700.00 | Window Closed / Lapsed |