US3562441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recording and/or reproducing apparatus with circuit to insert ac signal into amplifier to indicate battery condition
Assignee: US Philips Corp
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Filing: 1967-09-07
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Granted: 1971-02-09
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Expires: 1987-09-07
Abstract
Abstract A battery operated tape recorder includes a speed control element in series with the tape drive motor. The speed control element produces an AC signal voltage in the audio frequency range in the motor circuit. A manually operable switch establishes an AC connection between the motor circuit and the recorder amplifier for coupling the audio frequency signal to the recorder loudspeaker. The condition of the battery can be easily checked by merely operating the manual switch. The presence or absence of an audio tone indicates the condition of the battery.
Inventors
- 👤 Hermann Bretschneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:56
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B19/28; G11B15/00; G11B15/18; G11B15/46; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3018; G11B2220/00; G11B2220/90
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
In a sound transducing apparatus having an amplfier for recording and/or acoustically reproducing electric signals and a battery supplied motor, the improvement comprising a motor speed control element connected in series with said motor, alternating current connection means adapted to be connected in circuit between the input of one stage of the amplifier and a junction point in the motor circuit that includes said control element and where and AC voltage is developed, and circuit means including a manually operable switch for selectively connecting said AC connection means in circuit via the reference potentials of the amplifier and motor circuits thereby to couple said AC voltage to said amplifier input.
Claim 2
Dependent Claim
110 words
In a sound transducing apparatus having an amplfier for recording and/or acoustically reproducing electric signals and a battery supplied motor, the improvement comprising a motor speed control element connected in series with said motor, alternating current connection means adapted to be connected in circuit between the input of one stage of the amplifier and a junction point in the motor circuit that includes said control element and where and AC voltage is developed, and circuit means including a manually operable switch for selectively connecting said AC connection means in circuit via the reference potentials of the amplifier and motor circuits thereby to couple said AC voltage to said amplifier input.
Claim 3
Dependent Claim
105 words
An apparatus as claimed in claim 1 wherein the control element comprises a control transistor with its emitter-collector path connected in the motor circuit, means coupling the base of said transistor to the motor circuit so that the collector current is continuously controlled in accordance with the motor voltage and wherein the current circuit of the AC connection means includes the emitter-collector path of the control transistor, said apparatus further comprising a potentiometer comprising a threshold device and a resistor connected for direct current in parallel with the transistor emitter-collector path, the AC connection extending from a tap on said potentiometer to said amplifier input.
Claim 4
Dependent Claim
72 words
An apparatus as claimed in claim 1 further comprising switching means for switching said apparatus between the recording position and the playback position, the manual switch being operable to connect said AC connection means in circuit so as to record marks on the record carrier in the recording position and to check the value of the battery voltage in the playback position by selectively coupling said AC voltage to said amplifier input.
Claim 5
Dependent Claim
114 words
A sound transducing system comprising, a source of DC voltage, a motor adapted to drive a record carrier, a current control element adapted to pass a current in accordance With the motor speed, means connecting said voltage source, said motor and said control element in series circuit, an amplifier having an output for supplying signals to the system transducing means, a switch, AC coupling means, and circuit means including said switch for selectively connecting said AC coupling means between a given input of the amplifier and a junction point in the motor circuit at which an AC voltage is developed thereby to couple said AC voltage from the junction point to said amplifier input.
Claim 6
Dependent Claim
114 words
A sound transducing system comprising, a source of DC voltage, a motor adapted to drive a record carrier, a current control element adapted to pass a current in accordance With the motor speed, means connecting said voltage source, said motor and said control element in series circuit, an amplifier having an output for supplying signals to the system transducing means, a switch, AC coupling means, and circuit means including said switch for selectively connecting said AC coupling means between a given input of the amplifier and a junction point in the motor circuit at which an AC voltage is developed thereby to couple said AC voltage from the junction point to said amplifier input.
Claim 7
Dependent Claim
29 words
A system as claimed in claim 4 wherein said AC coupling means comprises a capacitor connected in series with said switch between said amplifier input and said junction point.
Claim 8
Dependent Claim
20 words
A system as claimed in claim 5 wherein said control element comprises a centrifugal switch coupled to the motor shaft.
Claim 9
Dependent Claim
57 words
A system as claimed in claim 4 wherein said AC coupling means comprises a capacitor and said control element comprises a transistor connected with its emitter-collector path in said series circuit, and means coupling the base electrode of said transistor to the motor so that the collector current is continuously controlled in accordance with the motor voltage.
Claim 10
Dependent Claim
34 words
A system as claimed in claim 7 wherein said base electrode coupling means comprises a bridge circuit having input terminals connected across the motor terminals and an output coupled to said transistor base electrode.
Claim 11
Dependent Claim
75 words
A system as claimed in claim 4 wherein said control element comprises a transistor connected with its emitter-collector path in said series circuit and its base electrode controlled by the motor voltage, and wherein said AC coupling means comprises, a threshold device, an impedance element, means serially connecting said threshold device and said impedance element in parallel with the transistor emitter-collector path, and a capacitor connected in series with said switch to said amplifier input.
Claim 12
Dependent Claim
41 words
A system as claimed in claim 9 wherein said threshold device comprises a semiconductor diode, said AC coupling means further comprising means serially connecting said diode, said capacitor and said switch between said amplifier input and said motor circuit junction point.
Claim 13
Dependent Claim
34 words
A system as claimed in claim 9 wherein said DC voltage source comprises a storage battery and wherein said threshold device comprises a semiconductor diode and a source of DC bias voltage connected thereto.
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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |