US3748591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Illumination activated transistor relaxation oscillator
Assignee: RCA Corp
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Filing: 1972-03-29
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Granted: 1973-07-24
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Expires: 1992-03-29
Abstract
Abstract An illumination activated circuit for supplying power from an oscillatory source to a load. A light sensitive device is arranged in the output circuit of the source such that the signal provided by the source to the load is initiated only when illumination above a certain intensity is received by the device, the device being in effect a dynamic load for the source.
Inventors
- 👤 A Visioli
- 👤 H Wittlinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:42
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/78; H03K17/795
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
354 words
An illumination activated circuit for providing power to a load comprising: an amplifier having a pair of input terminals and a pair of output terminals; a first and second emitter follower circuit each having an input terminal and an output terminal, the input terminal of the first emitter follower circuit being connected to one output terminal of the amplifier, the input terminal of the second emitter follower circuit being connected to the other output terminal of the amplifier; a first and second transistor each having a control electrode and two main electrodes, the control electrode of the first transistor being connected to the output terminal of the first emitter follower circuit, the control electrode of the second transistor being connected to the output terminal of the second emitter follower circuit, one main electrode of each of said transistors being connected to a point of reference potential; a resistive means for connecting the other main electrode of the second transistor to one of the input terminals of said amplifier; capacitive means connected between said one input terminal of said amplifier and said point of reference potential; a parallel RC network connecting the other main electrode of the second transistor to the other amplifier input terminal; a source of potential; a first and second resistor serially connected between said source of potential and said point of reference potential; means for connecting the other input terminal of the amplifier to a point between said first and second resistors; a light sensitive device having an electrical resistance characteristic which varies with illumination thereon, said device exhibiting a relatively high electrical resistance in the absence of illumination thereon and a relatively low electrical resistance in the presence of illumination thereon, said device being connected between the other main electrode of the second transistor and said source of potential; means for connecting the other main electrode of the first transistor to said source of potential; and means adapted for connecting said load to the other main electrode of said first transistor; said load being provided with power only in the presence of illumination of a certain intensity on said device.
Claim 2
Dependent Claim
354 words
An illumination activated circuit for providing power to a load comprising: an amplifier having a pair of input terminals and a pair of output terminals; a first and second emitter follower circuit each having an input terminal and an output terminal, the input terminal of the first emitter follower circuit being connected to one output terminal of the amplifier, the input terminal of the second emitter follower circuit being connected to the other output terminal of the amplifier; a first and second transistor each having a control electrode and two main electrodes, the control electrode of the first transistor being connected to the output terminal of the first emitter follower circuit, the control electrode of the second transistor being connected to the output terminal of the second emitter follower circuit, one main electrode of each of said transistors being connected to a point of reference potential; a resistive means for connecting the other main electrode of the second transistor to one of the input terminals of said amplifier; capacitive means connected between said one input terminal of said amplifier and said point of reference potential; a parallel RC network connecting the other main electrode of the second transistor to the other amplifier input terminal; a source of potential; a first and second resistor serially connected between said source of potential and said point of reference potential; means for connecting the other input terminal of the amplifier to a point between said first and second resistors; a light sensitive device having an electrical resistance characteristic which varies with illumination thereon, said device exhibiting a relatively high electrical resistance in the absence of illumination thereon and a relatively low electrical resistance in the presence of illumination thereon, said device being connected between the other main electrode of the second transistor and said source of potential; means for connecting the other main electrode of the first transistor to said source of potential; and means adapted for connecting said load to the other main electrode of said first transistor; said load being provided with power only in the presence of illumination of a certain intensity on said device.
Claim 3
Dependent Claim
119 words
The circuit according to claim 1 wherein said means adapted for connecting said load to said other main electrode of said first transistor comprises: a third and fourth transistor each having a control electrode and two main electrodes, the control electrode of the third transistor being connected to the other main electrode of the first transistor, one main electrode of the third transistor being connected to the source of potential, the other main electrode of the third transistor being connected to the control electrode of the fourth transistor, one main electrode of the fourth transistor being connected to said point of reference potential and said load being connected in circuit with the other main electrode of said fourth transistor.
Claim 4
Dependent Claim
215 words
An illumination activated circuit for providing power to a load, said circuit compriSing: an oscillator means having first and second input terminals and first and second output terminals, said oscillator means providing a first signal at the first output terminal thereof and a second signal at the second output terminal thereof, said first signal being 180 degrees out of phase with respect to said second signal; means for connecting said load in circuit with the first output terminal of said oscillator means; a light sensitive device connected in circuit with the second output terminal of said oscillator means, said device having an electrical resistance characteristic which varies with illumination thereon, said device exhibiting a relatively high electrical resistance in the absence of illumination thereon and a relatively low electrical resistance in the presence of illumination thereon; a first feedback path coupling the second output terminal of the oscillator means to the first input terminal of the oscillator means; a second feedback path coupling the second output terminal of the oscillator means to the second input terminal of the oscillator means; means for applying a source of biasing potential to said oscillator means; said oscillator means providing oscillations and power to said load only in the presence of illumination above a certain intensity on said device.
Claim 5
Dependent Claim
215 words
An illumination activated circuit for providing power to a load, said circuit compriSing: an oscillator means having first and second input terminals and first and second output terminals, said oscillator means providing a first signal at the first output terminal thereof and a second signal at the second output terminal thereof, said first signal being 180 degrees out of phase with respect to said second signal; means for connecting said load in circuit with the first output terminal of said oscillator means; a light sensitive device connected in circuit with the second output terminal of said oscillator means, said device having an electrical resistance characteristic which varies with illumination thereon, said device exhibiting a relatively high electrical resistance in the absence of illumination thereon and a relatively low electrical resistance in the presence of illumination thereon; a first feedback path coupling the second output terminal of the oscillator means to the first input terminal of the oscillator means; a second feedback path coupling the second output terminal of the oscillator means to the second input terminal of the oscillator means; means for applying a source of biasing potential to said oscillator means; said oscillator means providing oscillations and power to said load only in the presence of illumination above a certain intensity on said device.
Claim 6
Dependent Claim
158 words
The circuit according to claim 3 wherein said oscillator means comprises: a differential amplifier having a pair of input terminals corresponding to said oscillator means first and second input terminals and a pair of output terminals; first and second emitter follower circuits each having an input terminal and an output terminal, the first emitter follower input terminal being connected to one differential amplifier output terminal, the second emitter follower circuit input terminal being connected to the other differential amplifier output terminal; first and second drive transistors each having two main electrodes and a control electrode, the control electrodes of said first and second drive transistors being respectively connected to said first and second emitter follower output terminals, one main electrode of each of said drive transistors being adapted for connection to a point of reference potential, the other main electrode of said first and second drive transistors corresponding respectively to said first and second oscillator means output terminals.
Claim 7
Dependent Claim
28 words
The circuit according to claim 3 wherein said first feedback path comprises a resistance path and wherein said second feedback path comprises a parallel resistor and capacitor combination.
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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |