US3732443A
Expired / Lapsed
US
⏱️ 0.0 years remaining
On-off detection device
Assignee: RENKO ASS
•
Filing: 1971-05-12
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Granted: 1973-05-08
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Expires: 1991-05-12
Abstract
Abstract The invention relates to an on - off detecting device embodying a Wheatstone Bridge, wherein one leg of the bridge accommodates a resistance effect element which changes resistance value upon sensing a phenomenon, the change of resistance driving a differential input, high gain, common mode rejection amplifier into oscillation through positive feedback, and shutting off the amplifier through negative feedback.
Inventors
- 👤 R Lovrenich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:23
CPC Classifications
G; G01; G01R; G01R17/00; G01R17/10; G01R17/105; H; H03; H03K; H03K17/00; H03K17/94; H03K17/945
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
197 words
A closed loop bi-stable oscillator system comprising: a Wheatstone Bridge with four resistance legs including means in one leg adapted to accommodate a resistance effect element; a first output means between two legs of said Wheatstone Bridge; a second output means between the other two legs of said Wheatstone Bridge; a differential input, high gain, common mode rejection amplifier having a feedback means non-inductively connected to the input of said Wheatstone Bridge, having its positive input connected to the first output means of said Wheatstone Bridge, and having its negative input connected to the second output means of said Wheatstone Bridge; a single frequency selective element disposed in the bridgeamplifier circuit; wherein a change in resistance value of said resistance effect element resulting from detection of a phenomenon, changes the state of balance of the Wheatstone Bridge, causing a voltage input into said amplifier from said bridge circuit to drive said amplifier; and wherein a voltage signal of one polarity causes the amplifier to break into oscillation to drive said bridge and a voltage signal of opposite polarity causes sharp cut off of said oscillation; and means to connect a load to the output of said amplifier.
Claim 2
Dependent Claim
197 words
A closed loop bi-stable oscillator system comprising: a Wheatstone Bridge with four resistance legs including means in one leg adapted to accommodate a resistance effect element; a first output means between two legs of said Wheatstone Bridge; a second output means between the other two legs of said Wheatstone Bridge; a differential input, high gain, common mode rejection amplifier having a feedback means non-inductively connected to the input of said Wheatstone Bridge, having its positive input connected to the first output means of said Wheatstone Bridge, and having its negative input connected to the second output means of said Wheatstone Bridge; a single frequency selective element disposed in the bridgeamplifier circuit; wherein a change in resistance value of said resistance effect element resulting from detection of a phenomenon, changes the state of balance of the Wheatstone Bridge, causing a voltage input into said amplifier from said bridge circuit to drive said amplifier; and wherein a voltage signal of one polarity causes the amplifier to break into oscillation to drive said bridge and a voltage signal of opposite polarity causes sharp cut off of said oscillation; and means to connect a load to the output of said amplifier.
Claim 3
Dependent Claim
54 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein the resistance effect element is light sensitive and said device additionally comprises a light source and a light directing means for directing said light onto said element; and wherein interruption of said light effects a change in the resistance of said element.
Claim 4
Dependent Claim
34 words
A closed loop bi-stable oscillator system as claimed in claim 2 wherein the light source is connected to the amplifier output so that said light source blinks in relation to the amplifier output signal.
Claim 5
Dependent Claim
22 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein the resistance effect element is sensitive to a magnetic field.
Claim 6
Dependent Claim
66 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein the resistance effect element is a tuned circuit including a capacitor and a coil sensitive to the presence of an electrical conductor in its proximity to change the Q of the coil and the effective resistance of the tuned circuit in the bridge; and the resistance effect element is also the frequency selective element.
Claim 7
Dependent Claim
43 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein the resistance effect element is a heat sensitive element which changes resistance with a change in heat and which senses a change of temperature occurring in the proximity of said element.
Claim 8
Dependent Claim
27 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein the resistance effect element is an element which changes resistance with a change in motion.
Claim 9
Dependent Claim
74 words
A closed loop bi-stable oscillator system as claimed in claim 7 wherein the resistance effect element comprises a speaker device including a cone, a core, a coil wound on said core and a capacitor in parallel with said coil; said speaker cone sensing a change in surroundings and responding through a change in motion to alter the effective resistance of said resistance effect element; and the resistance effect element is the frequency selective element.
Claim 10
Dependent Claim
27 words
A closed loop bi-stable oscillator system as claimed in claim 1 wherein a pair of back-to-back diodes are disposed between one bridge output and one amplifier input.
Claim 11
Dependent Claim
29 words
A closed loop bi-stable oscillator system as claimed in claim 1 which is constructed and arranged so that the resistance effect element can also be the frequency selective element.
References Cited (Backward Citations)
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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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |