US3801837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photocoupling line isolation
Assignee: Eaton Corp
•
Filing: 1972-12-07
•
Granted: 1974-04-02
•
Expires: 1992-12-07
Abstract
Abstract A signal isolation and noise suppression circuit wherein electrooptical signals from a light-emitting diode of a signal source circuit are coupled to a phototransistor of a signal receiving circuit while physically isolating the signal receiving circuit from the source. The development also comprises a noise suppressing circuit.
Inventors
- 👤 L Pease
- 👤 R Huggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:02
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/42; H04; H04B; H04B10/00; H04B10/80; H04B10/801; H04B10/802
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
63 words
A signal isolation system comprising: a source of electronic signals; an input circuit, receiving said electronic signals, comprising a light-emitting diode serving to optically transmit signals received from said source; an output circuit electrically isolated from the input circuit comprising a phototransistor receiving said optical signals and creating electronic signals therefrom and a Schmitt trigger circuit connected to the collector of said phototransistor.
Claim 2
Dependent Claim
63 words
A signal isolation system comprising: a source of electronic signals; an input circuit, receiving said electronic signals, comprising a light-emitting diode serving to optically transmit signals received from said source; an output circuit electrically isolated from the input circuit comprising a phototransistor receiving said optical signals and creating electronic signals therefrom and a Schmitt trigger circuit connected to the collector of said phototransistor.
Claim 3
Dependent Claim
50 words
The system of claim 1 wherein said Schmitt trigger circuit comprises a NAND gate having one input connected to receive electronic signals from said phototransistor and the remainder of its inputs connected in common to a voltage source and a resistor connected between said one input and said voltage source.
Claim 4
Dependent Claim
30 words
The system of claim 1 further comprising resistance means connected in series between said source and said light-emitting diode to limit the magnitude of signals passed to said light-emitting diode.
Claim 5
Dependent Claim
22 words
The system of claim 1 further comprising noise suppression circuitry comprising capacitor means bridging between the base and emitter of the phototransistor.
Claim 6
Dependent Claim
108 words
A signal isolation system comprising: a source of input electronic signals; an input circuit comprising a light-emitting diode receiving said input electronic signals from said source and transmitting corresponding optical signals; an output circuit electrically isolated from the input circuit comprising a phototransistor the base of which is in optical communication with said light-emitting diode to receive said optical signals, switch means connected to the collector of said phototransistor and being switched by said phototransistor including a logic gate having a conductive state which is changed when the phototransistor is conductive, and noise suppression circuitry comprising capacitor means bridging between the base and the emitter of the phototransistor.
Claim 7
Dependent Claim
108 words
A signal isolation system comprising: a source of input electronic signals; an input circuit comprising a light-emitting diode receiving said input electronic signals from said source and transmitting corresponding optical signals; an output circuit electrically isolated from the input circuit comprising a phototransistor the base of which is in optical communication with said light-emitting diode to receive said optical signals, switch means connected to the collector of said phototransistor and being switched by said phototransistor including a logic gate having a conductive state which is changed when the phototransistor is conductive, and noise suppression circuitry comprising capacitor means bridging between the base and the emitter of the phototransistor.
References Cited (Backward Citations)
US3708672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |