US3612997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitor apparatus including a reference capacitor for controlling the current flow through a capacitance being measured
Assignee: Individual
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Filing: 1970-02-18
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Granted: 1971-10-12
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Expires: 1990-02-18
Abstract
Abstract An apparatus for testing an item, such as a capacitor, to determine its capacitance value is described. A timing and reference capacitor is charged at a constant rate from a constant current source. The test capacitor charges at a related rate through a source follower transistor circuit which includes a current meter. The timing and reference, and the test capacitors are both discharged by a unijunction transistor when a predetermined potential level is reached. Thereafter, the charging cycle reoccurs.
Inventors
- 👤 John Paulkovich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:16
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2605
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
137 words
Apparatus for measuring the capacitance of an item comprising: constant current means for generating a constant current flow; storage means connected to said constant current means for storing the current generated by said constant current means; source follower means connected to said storage means and adapted for connection to said item whose capacitance is to be measured for controlling the application of current to said item in accordance with the voltage level of the current stored by said storage means, said source follower means including an indicator means for indicating the amount of current flow passing through said source follower means; and, discharge means connected to said storage means and to said source follower means for discharging the current stored by said storage means and the current stored by said item whose capacitance is to be measured.
Claim 2
Dependent Claim
137 words
Apparatus for measuring the capacitance of an item comprising: constant current means for generating a constant current flow; storage means connected to said constant current means for storing the current generated by said constant current means; source follower means connected to said storage means and adapted for connection to said item whose capacitance is to be measured for controlling the application of current to said item in accordance with the voltage level of the current stored by said storage means, said source follower means including an indicator means for indicating the amount of current flow passing through said source follower means; and, discharge means connected to said storage means and to said source follower means for discharging the current stored by said storage means and the current stored by said item whose capacitance is to be measured.
Claim 3
Dependent Claim
25 words
Apparatus for measuring the capacitance of an item as claimed in claim 1 wherein said storage means includes at least one timing and reference capacitor.
Claim 4
Dependent Claim
21 words
Apparatus for measuring the capacitance of an item as claimed in claim 2 wherein said discharge means is a relaxation oscillator.
Claim 5
Dependent Claim
20 words
Apparatus for measuring the capacitance of an item as claimed in claim 3 wherein said indicator means is a meter.
Claim 6
Dependent Claim
39 words
Apparatus for measuring the capacitance of an item as claimed in claim 4 wherein said constant current means include a constant current diode and a voltage source connected in series with said at least one reference and timing capacitor.
Claim 7
Dependent Claim
53 words
Apparatus for measuring the capacitance of an item as claimed in claim 5 wherein said relaxation oscillator is a unijunction transistor having its bases connected across the terminals of said voltage source and its emitter connected to the junction between said constant current diode and said at least one reference and timing capacitor.
Claim 8
Dependent Claim
57 words
Apparatus for measuring the capacitance of an item as claimed in claim 6 wherein said source follower means is a transistor having its emitter adapted for connection to said item whose capacitance is to be measured, its collector connected through said meter to said voltage source and its base connected to the emitter of said unijunction transistor.
Claim 9
Dependent Claim
29 words
Apparatus for measuring the capacitance of an item as claimed in claim 7 including a diode connected between the base of said transistor and the emitter of said transistor.
Claim 10
Dependent Claim
39 words
Apparatus for measuring the capacitance of an item as claimed in claim 2 wherein said constant current means includes a constant current diode and a voltage source connected in series with said at least one reference and timing capacitor.
Claim 11
Dependent Claim
53 words
Apparatus for measuring the capacitance of an item as claimed in claim 9 wherein said discharge means is a unijunction transistor having its bases connected across the terminals of said voltage source and its emitter connected to the junction between said constanT current diode and said at least one reference and timing capacitor.
Claim 12
Dependent Claim
75 words
Apparatus for measuring the capacitance of an item as claimed in claim 10 wherein said source follower means is a high-gain transistor and said indicator is a meter, the emitter of said high-gain transistor adapted for connection to said item whose capacitance is to be measured, the collector of said high-gain transistor connected through said meter to said voltage source and the base of said high-gain transistor connected to the emitter of said unijunction transistor.
Claim 13
Dependent Claim
51 words
Apparatus for measuring the capacitance of an item as claimed in claim 1 wherein said constant current means includes a field effect transistor and a voltage source connected so that the source and drain terminals of said field effect transistor are in series with said voltage source and said storage means.
Claim 14
Dependent Claim
114 words
Apparatus for measuring the capacitance of an item as claimed in claim 12 wherein said storage means includes a plurality of capacitors and a first multiterminal switch, said plurality of capacitors being connected at one end to predetermined terminals of said first multiterminal switch and at the other end to one side of said voltage source; said storage means further including a plurality of resistors and a second multiterminal switch, said plurality of resistors being connected at one end to predetermined terminals of said second multiterminal switch and at the other end to the source terminal of said field effect transistor; the wiper terminals of said first and second multiterminal switches being connected together.
Claim 15
Dependent Claim
55 words
Apparatus for measuring the capacitance of an item as claimed in claim 13 wherein said discharge means comprises a unijunction transistor having its bases connected across the terminals of said voltage source and having its emitter connected to the gate of said field effect transistor and to the wiper terminal of said second multiterminal switch.
Claim 16
Dependent Claim
78 words
Apparatus for measuring the capacitance of an item as claimed in claim 14 wherein said source follower means comprises a transistor and said indicator means is a current meter, said transistor having its base connected to the emitter of said unijunction transistor, its emitter connected to a first test terminal and its collector through said current meter to one side of said voltage source, the other side of said voltage source being connected to a second test terminal.
Claim 17
Dependent Claim
58 words
Apparatus for measuring the capacitance of an item as claimed in claim 15 including four diodes, the first and second diodes being connected parallel opposing between the wiper terminals of said first and second switches, the third diode being connected in parallel with said meter, and the fourth diode being connected across the emitter-base terminals of said transistor.
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) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |