US3676633A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic trimming of microelectronic resistors
Assignee: ADM Tronics Unlimited Inc
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Filing: 1971-05-26
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Granted: 1972-07-11
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Expires: 1991-05-26
Abstract
Abstract An electronic technique for changing the ohmic values of microelectronic resistors formed on a substrate, so as to either increase or decrease the values thereof without affecting their physical qualities. To bring about a decrease in value, the surface of the resistor is subjected to a corona discharge produced by radio-frequency energy having a low-frequency amplitude modulation component. The same energy source is used to effect an increase in ohmic value, this being effected by passing a heating current through the body of the resistor.
Inventors
- 👤 Alfonso Di Mino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:32
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/22; H01C17/26; H01C17/265; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
130 words
Apparatus for electronically trimming the ohmic value of a printed circuit resistor, said apparatus comprising: A. a high-frequency oscillator having a resonator coil to produce R-F energy, B. an audio-frequency generator coupled to the oscillator to amplitude-modulate the R-F energy, C. a step-up coil coupled to the resonator to derive a high voltage therefrom sufficient to produce a corona discharge, D. a step-down coil coupled to the resonator to derive a low voltage therefrom sufficient to produce a heating current, E. a first probe connected to said step-up coil to produce a corona discharge when brought into the vicinity of a point on said resistor, and F. a second probe connected to said step-down coil to produce a heating current when brought into contact with a point on said resistor.
Claim 2
Dependent Claim
130 words
Apparatus for electronically trimming the ohmic value of a printed circuit resistor, said apparatus comprising: A. a high-frequency oscillator having a resonator coil to produce R-F energy, B. an audio-frequency generator coupled to the oscillator to amplitude-modulate the R-F energy, C. a step-up coil coupled to the resonator to derive a high voltage therefrom sufficient to produce a corona discharge, D. a step-down coil coupled to the resonator to derive a low voltage therefrom sufficient to produce a heating current, E. a first probe connected to said step-up coil to produce a corona discharge when brought into the vicinity of a point on said resistor, and F. a second probe connected to said step-down coil to produce a heating current when brought into contact with a point on said resistor.
Claim 3
Dependent Claim
29 words
Apparatus as set forth in claim 1, wherein said step-up coil is a multi-turn coil of high inductance and said step-down coil is a single-turn coil of low inductance.
Claim 4
Dependent Claim
18 words
Apparatus as set forth in claim 1, wherein said oscillator operates at a frequency of about one megacycle.
Claim 5
Dependent Claim
18 words
Apparatus as set forth in claim 1, wherein said generator operates at a frequency of about 3,000 Hz.
References Cited (Backward Citations)
US3486221A
Cited
US3596039A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |