US4238726A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring low impedance for obtaining unknown capacitance and/or resistance
Assignee: Individual
•
Filing: 1979-02-02
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Granted: 1980-12-09
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Expires: 1999-02-02
Abstract
Abstract A method for accurately measuring the capacitances and loss resistances of specimens of an unknown impedance (hereinafter referred to as the "specimen"). The measured values of the capacitances are unaffected by the resistances of the specimens when the equivalent parallel resistances of the specimens vary from infinity to 30 ohms. Several meters' length of HF coaxial cable can be used in place of a lead-wire connecting the measuring part and electrodes.
Inventors
- 👤 Bunjiro Ichijo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:32
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
268 words
In a method of measuring a low impedance for obtaining an unknown capacitance and/or resistance of the type wherein: forming a low impedance measuring circuit with (a) a resonant circuit including capacitances C 1 and C 2 connected in series with each other, (b) a high frequency source to supply the resonant circuit with a high frequency voltage, (c) an amplitude detecting circuit respectively coupled electromagnetically with the high frequency source and the resonant circuit for measuring the resonant current of the resonant circuit, (d) a phase detecting circuit respectively coupled electromagnetically with the high frequency source and the resonant circuit for measuring the phase of the resonant current of the resonant circuit, and (e) means for connecting the connecting point between the capacitances C 2 and C 1 of the resonant circuit with electrodes to be connected with the impedance to be measured so as to connect the impedance to be measured with the condenser C 2 in parallel; adjusting the resonant circuit to the resonant condition before connecting the impedance to be measured; connecting then the impedance to be measured and adjusting the capacitance C 2 of the resonant circuit to form again the resonant condition; and obtaining the unknown capacitance of the impedance to be measured from the extent of the adjustment of the capacitance C 2 and the unknown resistance from the indication of the amplitude detector; the improvement comprising: forming the means for connecting with an inductance L x so as to satisfy the equation ω 2 C 2 L x =1 where ω is the angular frequency of the high frequency source.
Claim 2
Dependent Claim
268 words
In a method of measuring a low impedance for obtaining an unknown capacitance and/or resistance of the type wherein: forming a low impedance measuring circuit with (a) a resonant circuit including capacitances C 1 and C 2 connected in series with each other, (b) a high frequency source to supply the resonant circuit with a high frequency voltage, (c) an amplitude detecting circuit respectively coupled electromagnetically with the high frequency source and the resonant circuit for measuring the resonant current of the resonant circuit, (d) a phase detecting circuit respectively coupled electromagnetically with the high frequency source and the resonant circuit for measuring the phase of the resonant current of the resonant circuit, and (e) means for connecting the connecting point between the capacitances C 2 and C 1 of the resonant circuit with electrodes to be connected with the impedance to be measured so as to connect the impedance to be measured with the condenser C 2 in parallel; adjusting the resonant circuit to the resonant condition before connecting the impedance to be measured; connecting then the impedance to be measured and adjusting the capacitance C 2 of the resonant circuit to form again the resonant condition; and obtaining the unknown capacitance of the impedance to be measured from the extent of the adjustment of the capacitance C 2 and the unknown resistance from the indication of the amplitude detector; the improvement comprising: forming the means for connecting with an inductance L x so as to satisfy the equation ω 2 C 2 L x =1 where ω is the angular frequency of the high frequency source.
Claim 3
Dependent Claim
54 words
A method of measuring a low impedance for obtaining an unknown capacitance and/or resistance according to claim 1, wherein the inductance L x comprises the series circuit of an inductance L i and a capacitance C i so that the equation ω 2 C 2 (L i -1/ω 2 C i )=1 is satisfied.
Claim 4
Dependent Claim
34 words
A method of measuring a low impedance for obtaining an unknown capacitance and/or resistance according to claim 2, wherein the connecting means is a series circuit of a coaxial cable and a variable capacitor.
Claim 5
Dependent Claim
34 words
A method of measuring a low impedance for obtaining an unknown capacitance and/or resistance according to claim 1, wherein the resonant circuit is a parallel resonant circuit coupled electrostatically with the high frequency source.
Claim 6
Dependent Claim
34 words
A method of measuring a low impedance for obtaining an unknown capacitance and/or resistance according to claim 1, wherein the resonant circuit is a series resonant circuit electromagnetically coupled with the high frequency source.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-09 | 1984-06-09 | 1984-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-09 | 1988-06-09 | 1988-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-09 | 1992-06-09 | 1992-12-09 | $7700.00 | Window Closed / Lapsed |