US3821600A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable intensity illuminator
Assignee: Litton Marine Systems Inc
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Filing: 1972-06-29
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Granted: 1974-06-28
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Expires: 1992-06-29
Abstract
Abstract Variable illumination apparatus includes means for closely controlling the voltage to a lamp so that low values of illumination can be readily adjusted. The frequency of an astable multivibrator is adjusted through a potentiometer coupling the astable multivibrator to a voltage source. Each pulse from the astable multivibrator drives a monostable multivibrator into its quasi-stable state. The time that the monostable multivibrator remains in the quasi-stable state is adjusted by the same potentiometer that adjusts the frequency of the astable multivibrator in such a way that the quasi-stable time duration increases as the pulse repetition rate of the astable multivibrator increases. The circuit is proportioned so that the quasi-stable pulse duration is longer than the pulse repetition period of the astable multivibrator when the astable multivibrator is operating at its maximum rate, so that under these conditions the monostable multivibrator is clamped in its quasi-stable state. The load is taken from the complementary output terminal of the monostable multivibrator so that lamp voltage decreases to zero as the repetition rate and pulse duration is increased.
Inventors
- 👤 C Wesner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:40
CPC Classifications
B; B63; B63B; B63B45/00; B63B45/06; H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H03; H03K; H03K3/00; H03K3/02; H03K3/027; H03K3/03; H05; H05B; H05B47/00; H05B47/10; B63B2045/005
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
220 words
Wide range, variable illumination apparatus comprising a lamp, monostable multivibrator means, an astable multivibrator coupled to drive said monostable multivibrator means from a stable state into a quasi-stable state in response to a selected edge of an output pulse from the astable multivibrator, first means to vary the pulse repetition rate of said astable multivibrator, second means to vary the quasi-stable state duration of said monostable multivibrator, said first and second means including a potentiometer having an adjustable arm connected to a source of d.c. voltage suitable for energizing said multivibrators, said astable multivibrator being coupled to one end of the resistance element of said potentiometer through a first RC means, said monostable multivibrator being coupled to the other end of said resistance element through a second RC means so as to increase and decrease the pulse repetition rate of said astable multivibrator as the quasi-stable state duration of said monostable multivibrator is simultaneously increased and decreased respectively, said first and second multivibrators being adjusted so that the quasi-stable pulse duration of said monostable multivibrator is at least as long as the interpulse interval of the wave train from said astable multivibrator when the astable multivibrator is operating at its maximum pulse repetition rate, and means to energize said lamp only when the monostable multivibrator is in its stable state.
Claim 2
Dependent Claim
220 words
Wide range, variable illumination apparatus comprising a lamp, monostable multivibrator means, an astable multivibrator coupled to drive said monostable multivibrator means from a stable state into a quasi-stable state in response to a selected edge of an output pulse from the astable multivibrator, first means to vary the pulse repetition rate of said astable multivibrator, second means to vary the quasi-stable state duration of said monostable multivibrator, said first and second means including a potentiometer having an adjustable arm connected to a source of d.c. voltage suitable for energizing said multivibrators, said astable multivibrator being coupled to one end of the resistance element of said potentiometer through a first RC means, said monostable multivibrator being coupled to the other end of said resistance element through a second RC means so as to increase and decrease the pulse repetition rate of said astable multivibrator as the quasi-stable state duration of said monostable multivibrator is simultaneously increased and decreased respectively, said first and second multivibrators being adjusted so that the quasi-stable pulse duration of said monostable multivibrator is at least as long as the interpulse interval of the wave train from said astable multivibrator when the astable multivibrator is operating at its maximum pulse repetition rate, and means to energize said lamp only when the monostable multivibrator is in its stable state.
Claim 3
Dependent Claim
24 words
The apparatus of claim 1 wherein said monostable multivibrator has a complementary output terminal and said lamp is coupled to said complementary output terminal.
Claim 4
Dependent Claim
13 words
The apparatus of claim 2 wherein said selected edge is the trailing edge.
Claim 5
Dependent Claim
42 words
The apparatus of claim 2 wherein the multivibrators are packaged as an integrated circuit in which external R-C networks are used to adjust the pulse repetition rate and quasi-stable states of the astable and monostable multivibrator portions of the integrated circuit, respectively.
Claim 6
Dependent Claim
250 words
A wide range variable illumination circuit comprising a lamp, a source of d.c. voltage, an astable multivibrator, first variable R-C network means for coupling said source of d.c. to said astable multivibrator, the pulse repetition rate of said astable multivibrator being determined by the resistance and capacitance values of said first network, said first network including a potentiometer having an adjustable arm connected to said d.c. source and a resistance element having one end thereof coupled to said astable multivibrator whereby the pulse repetition rate of said astable multivibrator increases as said adjustable arm is positioned closer to said one end, a monostable multivibrator coupled to said astable multivibrator so as to be driven into its quasi-stable state in response to the trailing edge of a pulse from said astable multivibrator, second variable R-C network means for coupling said monostable multivibrator to said source of d.c. through the other end of said resistance element, said second network being arranged to increase the length of time that said monostable multivibrator remains in its quasi-stable state as said adjustable arm is moved away from said other end, said first and second networks being proportioned so that said monostable multivibrator remains in its quasi-stable state for a time period at least as long as the interpulse interval of the pulse train from said astable multivibrator when the astable multivibrator is operating at its maximum pulse repetition rate, and means to energize said lamp only when said monostable multivibrator is in its stable state.
Claim 7
Dependent Claim
250 words
A wide range variable illumination circuit comprising a lamp, a source of d.c. voltage, an astable multivibrator, first variable R-C network means for coupling said source of d.c. to said astable multivibrator, the pulse repetition rate of said astable multivibrator being determined by the resistance and capacitance values of said first network, said first network including a potentiometer having an adjustable arm connected to said d.c. source and a resistance element having one end thereof coupled to said astable multivibrator whereby the pulse repetition rate of said astable multivibrator increases as said adjustable arm is positioned closer to said one end, a monostable multivibrator coupled to said astable multivibrator so as to be driven into its quasi-stable state in response to the trailing edge of a pulse from said astable multivibrator, second variable R-C network means for coupling said monostable multivibrator to said source of d.c. through the other end of said resistance element, said second network being arranged to increase the length of time that said monostable multivibrator remains in its quasi-stable state as said adjustable arm is moved away from said other end, said first and second networks being proportioned so that said monostable multivibrator remains in its quasi-stable state for a time period at least as long as the interpulse interval of the pulse train from said astable multivibrator when the astable multivibrator is operating at its maximum pulse repetition rate, and means to energize said lamp only when said monostable multivibrator is in its stable state.
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) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |