Patent US4025850A successfully refreshed from Google Patents.
US4025850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Passive, solid state wide range voltage checker
Assignee: Individual
•
Filing: 1975-10-01
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Granted: 1977-05-24
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Expires: 1995-10-01
Abstract
Abstract A checker for a.c. and d.c. voltages in the range of 3 to 250 or more volts in which a single light emitting diode serves as an indicator for all voltages and the current through the light emitting diode is controlled by a transistor and a zener diode. The tester indicates a.c. or d.c. and polarity of d.c. voltages.
Inventors
- 👤 Joseph Spiteri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:11
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/145; G01R19/155; G01R19/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
123 words
A passive total solid state pocket size voltage checker operative for testing voltages within a range of 3 to 250 volts comprising a housing, an indicating circuit within the housing comprising a rectifier, a resistor, a transistor, and an indicator in series with a pair of leads, said leads extending from the housing and having free ends provided with terminals for connection across an unknown voltage, said transistor having its emitter and collector in series with said resistor and said indicator, and means connected in said circuit for limiting the sum of the voltage across the resistor plus the emitter to base voltage of the transistor, and the transistor sustaining all voltage in excess of the voltage drop across the indicator and resistor.
Claim 2
Dependent Claim
123 words
A passive total solid state pocket size voltage checker operative for testing voltages within a range of 3 to 250 volts comprising a housing, an indicating circuit within the housing comprising a rectifier, a resistor, a transistor, and an indicator in series with a pair of leads, said leads extending from the housing and having free ends provided with terminals for connection across an unknown voltage, said transistor having its emitter and collector in series with said resistor and said indicator, and means connected in said circuit for limiting the sum of the voltage across the resistor plus the emitter to base voltage of the transistor, and the transistor sustaining all voltage in excess of the voltage drop across the indicator and resistor.
Claim 3
Dependent Claim
14 words
The checker of claim 1 in which the indicator is a light emitting diode.
Claim 4
Dependent Claim
15 words
The checker of claim 1 in which the indicator is a sound emitter or like.
Claim 5
Dependent Claim
14 words
The checker of claim 1 in which the voltage limiting means is a zener.
Claim 6
Dependent Claim
14 words
The checker of claim 1 in which the voltage limiting means is a varistor.
Claim 7
Dependent Claim
15 words
The checker of claim 1 in which the voltage limiting means is a pn junction.
Claim 8
Dependent Claim
18 words
The checker of claim 1 in which the voltage limiting means is a semiconductor with a threshold voltage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |