Patent US3733597A successfully refreshed from Google Patents.
US3733597A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity detector and alarm utilizing field effect transistors
Assignee: United States Department of the Army
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Filing: 1969-08-29
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Granted: 1973-05-15
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Expires: 1989-08-29
Abstract
Abstract A proximity detector and alarm in which an antenna is connected to the gate of a metal oxide semiconductor field effect transistor (MOSFET) which causes a silicon controlled switch (SCS) to trigger a blocking oscillator.
Inventors
- 👤 G Healey
- 👤 J Nirschl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:23
CPC Classifications
G; G08; G08G; G08G1/00; G08G1/01; G08B; G08B13/00; G08B13/22; G08B13/26; H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/955
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
117 words
A proximity detector comprising: a metal oxide semiconductor field effect transistor (MOSFET) having gate, drain, and source electrodes; an antenna connected to said gate electrode, a high megohm resistor connected between said gate and said drain electrode, a voltage source, a load resistor connected between the negative end of said voltage source and the point common to the high megohm resistor and the drain electrode; a coaxial cable, a transistor having a base, emitter and collector, said collector connected to the negative terminal of said voltage source, said base connected to said drain electrode and, said emitter connected to a first end of said cable; and a recording means connected to a second end of said cable.
Claim 2
Dependent Claim
117 words
A proximity detector comprising: a metal oxide semiconductor field effect transistor (MOSFET) having gate, drain, and source electrodes; an antenna connected to said gate electrode, a high megohm resistor connected between said gate and said drain electrode, a voltage source, a load resistor connected between the negative end of said voltage source and the point common to the high megohm resistor and the drain electrode; a coaxial cable, a transistor having a base, emitter and collector, said collector connected to the negative terminal of said voltage source, said base connected to said drain electrode and, said emitter connected to a first end of said cable; and a recording means connected to a second end of said cable.
Claim 3
Dependent Claim
21 words
The circuit of claim 1 further comprising a filter connected between said second end of said cable and the recording means.
Claim 4
Dependent Claim
15 words
The circuit of claim 2 in which said filter is used to suppress 60 HZ.
Claim 5
Dependent Claim
43 words
The circuit of claim 1 further comprising: a zener diode connected between said source electrode and the positive terminal of said voltage source and, a zener diode connected between the first end of said cable and the positive terminal of said voltage source.
Claim 6
Dependent Claim
108 words
An alarm circuit comprising: a MOSFET having gate, drain and source electrodes; an antenna connected to said gate electrode, a high megohm resistor connected between said gate and said drain electrode, a cable at least ten feet in length, a silicon controlled switch having a first electrode connected to said drain electrode, a second electrode connected to said source electrode, a third electrode connected to ground and a fourth electrode connected to one end of said cable; a blocking oscillator connected between the second end of said cable and said source electrode and, a reset switch connected between said blocking oscillator and the second end of said cable.
Claim 7
Dependent Claim
108 words
An alarm circuit comprising: a MOSFET having gate, drain and source electrodes; an antenna connected to said gate electrode, a high megohm resistor connected between said gate and said drain electrode, a cable at least ten feet in length, a silicon controlled switch having a first electrode connected to said drain electrode, a second electrode connected to said source electrode, a third electrode connected to ground and a fourth electrode connected to one end of said cable; a blocking oscillator connected between the second end of said cable and said source electrode and, a reset switch connected between said blocking oscillator and the second end of said cable.
Claim 8
Dependent Claim
14 words
The circuit of claim 5 in which the blocking oscillator output is a loudspeaker.
Claim 9
Dependent Claim
25 words
The circuit of claim 5 in which a variable resistor is connected between said drain electrode and the first electrode of said silicon controlled switch.
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) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |