US3689832A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resistance tester for producing an audible tone that varies with the resistance
Assignee: Western Technical Products Inc
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Filing: 1970-05-01
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Granted: 1972-09-05
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Expires: 1990-05-01
Abstract
Abstract An audible resistance and electrical continuity tester in the form of a small self-contained hand tool hav-ing a speaker driven by a pulse generator, the frequency of which varies directly with measured resistances from a low audible pitch representing a zero resistance to a high audible pitch representing continuity to a relatively high resistance.
Inventors
- 👤 Alfonso Leto
- 👤 William R Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:25
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/50; G01R31/54
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
246 words
An audible, resistance and electrical continuity tester for generating an audible tone where frequency varies directly in accordance with the resistance of the component under test -high resistance, high frequency and low resistance, low frequency and having a speaker, a first test probe terminal, a second test probe terminal, said tester including an audio-frequency oscillator comprising a first circuit including a first transistor in series with said speaker, said first circuit being coupled across first and second terminals of a dc source, a second circuit including a second transistor having its collector coupled to the base of said first transistor for controlling said first circuit, the base of said second transistor being coupled to the emitter of said first transistor and the first terminal of the dc source, the emitter of said second transistor being coupled to said first test probe terminal, said second test probe terminal being coupled to the second terminal of said dc source, and a series RC circuit coupled between the base of said second transistor and the collector of said first transistor for producing oscillation at a frequency controlled by and directly related to the resistance of a component under test across said first and second test probe terminals, which resistance completes the circuit from said second transistor to the dc source so that if, and only if, the resistance under test completes said circuit, will current be drained from said dc source eliminating all need for switches in the oscillator.
Claim 2
Dependent Claim
246 words
An audible, resistance and electrical continuity tester for generating an audible tone where frequency varies directly in accordance with the resistance of the component under test -high resistance, high frequency and low resistance, low frequency and having a speaker, a first test probe terminal, a second test probe terminal, said tester including an audio-frequency oscillator comprising a first circuit including a first transistor in series with said speaker, said first circuit being coupled across first and second terminals of a dc source, a second circuit including a second transistor having its collector coupled to the base of said first transistor for controlling said first circuit, the base of said second transistor being coupled to the emitter of said first transistor and the first terminal of the dc source, the emitter of said second transistor being coupled to said first test probe terminal, said second test probe terminal being coupled to the second terminal of said dc source, and a series RC circuit coupled between the base of said second transistor and the collector of said first transistor for producing oscillation at a frequency controlled by and directly related to the resistance of a component under test across said first and second test probe terminals, which resistance completes the circuit from said second transistor to the dc source so that if, and only if, the resistance under test completes said circuit, will current be drained from said dc source eliminating all need for switches in the oscillator.
Claim 3
Dependent Claim
44 words
The continuity tester as claimed in claim 1 further including an elongated tubular housing with said first test probe mounted on said tubular housing, and said speaker and audio-frequency oscillator mounted within said housing so as to form a self contained hand-held testing device.
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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |