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Patent US4829290A successfully refreshed from Google Patents.
US4829290A
Expired / Lapsed
US
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Low voltage alert circuit
Assignee: Motorola Solutions Inc
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Filing: 1988-01-04
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Granted: 1989-05-09
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Expires: 2008-01-04
Abstract
Abstract The alert circuit includes a minimum number of inexpensive descrete electronic components to provide a flashing alert when battery voltage drops below a predetermined trigger voltage. A single unijunction transistor circuit functions as a combination low voltage detector and oscillator to output periodic pulses to an LED annunciator circuit when battery voltage is low.
Inventors
- 👤 Robert B. Ford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:09
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/80; G; G01; G01R; G01R19/00; G01R19/165; G01R19/16533; G01R19/16538; G01R19/16542; G08; G08B; G08B29/00; G08B29/18; G08B29/181
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
114 words
A low voltage alert circuit having first and second input terminals, comprising in combination: a three terminal relaxation device; a Zener diode coupled between the first and second input terminals of said low voltage alert circuit; a first resistor coupled between said Zener diode and a first terminal of said relaxation device; a capacitor coupled between said first terminal of said relaxation device and said second input terminal of the low voltage alert circuit; a second diode coupled between said first input terminal and a second terminal of said relaxation device; and a second resistor coupled between a third terminal of said relaxation device and an output terminal of said low voltage alert circuit.
Claim 2
Dependent Claim
114 words
A low voltage alert circuit having first and second input terminals, comprising in combination: a three terminal relaxation device; a Zener diode coupled between the first and second input terminals of said low voltage alert circuit; a first resistor coupled between said Zener diode and a first terminal of said relaxation device; a capacitor coupled between said first terminal of said relaxation device and said second input terminal of the low voltage alert circuit; a second diode coupled between said first input terminal and a second terminal of said relaxation device; and a second resistor coupled between a third terminal of said relaxation device and an output terminal of said low voltage alert circuit.
Claim 3
Dependent Claim
71 words
The low voltage alert circuit of claim 1, further comprising: a transistor having a first terminal coupled to said output terminal and a second terminal coupled to said second input terminal; a light emitting diode having a first terminal coupled to said first input terminal and to a third terminal of said transistor; and a switch coupled between a second terminal of said light emitting diode and said second input terminal.
Claim 4
Dependent Claim
25 words
The low voltage alert circuit of claim 1, in which a light emitting diode is operatively coupled to said output of the low alert circuit.
Claim 5
Dependent Claim
212 words
A low voltage alert circuit having first and second input terminal, comprising in combination; a programmable unijunction transistor; a Zener diode having a first terminal coupled to said second input termina; a first resistor coupled between said Zener diode and the anode of said unijunction transistor; a capacitor coupled between said anode of said unijunction transistor and said second input terminal; a second transistor having a first terminal coupled to said second input terminal; a second resistor coupled between the cathode of said unijunction transistor and a second terminal of said second transistor; a second diode having a first terminal coupled to an input terminal of said alert circuit; a third resistor coupled between a second terminal of said second diode and the gate of said unijunction transistor; a fourth resistor coupled between said second terminal of said second diode and said second input terminal; a fifth resistor coupled between a second terminal of said Zener diode and said input terminal; a light emitting diode having a first terminal coupled to a third terminal of said second transistor; a sixth resistor coupled between said first terminal of said light emitting diode and said input terminal; and a switch coupled between a second terminal of said light emitting diode and second input terminal.
Claim 6
Dependent Claim
212 words
A low voltage alert circuit having first and second input terminal, comprising in combination; a programmable unijunction transistor; a Zener diode having a first terminal coupled to said second input termina; a first resistor coupled between said Zener diode and the anode of said unijunction transistor; a capacitor coupled between said anode of said unijunction transistor and said second input terminal; a second transistor having a first terminal coupled to said second input terminal; a second resistor coupled between the cathode of said unijunction transistor and a second terminal of said second transistor; a second diode having a first terminal coupled to an input terminal of said alert circuit; a third resistor coupled between a second terminal of said second diode and the gate of said unijunction transistor; a fourth resistor coupled between said second terminal of said second diode and said second input terminal; a fifth resistor coupled between a second terminal of said Zener diode and said input terminal; a light emitting diode having a first terminal coupled to a third terminal of said second transistor; a sixth resistor coupled between said first terminal of said light emitting diode and said input terminal; and a switch coupled between a second terminal of said light emitting diode and second input terminal.
References Cited (Backward Citations)
US3810144A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |