Patent US3890465A successfully refreshed from Google Patents.
US3890465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangement for protection of a speaker system
Assignee: Victor Company of Japan Ltd
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Filing: 1973-07-10
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Granted: 1975-06-17
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Expires: 1993-07-10
Abstract
Abstract Two lines normally connect an amplifier to a speaker. An electronic circuit connected between the lines senses an excessively high power surge energizing a relay switch to disconnect one of the lines. When the power surge is over, the relay switch is de-energized automatically restoring the normal connections to the speaker.
Inventors
- 👤 Yasuo Kaizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:50
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/007; H02; H02H; H02H3/00; H02H3/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
212 words
A loudspeaker protection circuit for cutting off an input signal applied to a loudspeaker when the input signal exceeds a predetermined level, comprising: a. input means for receiving an input signal; b. output means for applying the input signal to said loudspeaker; c. circuit means including a relay having a normally closed contact electrically connecting said input means to said output means for applying the input signal to the output means; d. first rectifying means receptive of the input signal for developing a first rectified signal representative of the amplitude of the input signal; e. a control device having a conductive state and a nonconductive state and a control electrode for receiving a signal to control its conductive state; f. second rectifying means receptive of the input signal for developing a second rectified signal representative of the amplitude of the input signal; g. means applying said second rectified signal to said control electrode of said control element; and h. means electrically connecting said first rectifying means with said control device and said relay to energize said relay with said first rectified signal to open said normally closed contact and disconnect said output means from said input means when said first rectified signal exceeds a predetermined level determined by said second rectified signal.
Claim 2
Dependent Claim
212 words
A loudspeaker protection circuit for cutting off an input signal applied to a loudspeaker when the input signal exceeds a predetermined level, comprising: a. input means for receiving an input signal; b. output means for applying the input signal to said loudspeaker; c. circuit means including a relay having a normally closed contact electrically connecting said input means to said output means for applying the input signal to the output means; d. first rectifying means receptive of the input signal for developing a first rectified signal representative of the amplitude of the input signal; e. a control device having a conductive state and a nonconductive state and a control electrode for receiving a signal to control its conductive state; f. second rectifying means receptive of the input signal for developing a second rectified signal representative of the amplitude of the input signal; g. means applying said second rectified signal to said control electrode of said control element; and h. means electrically connecting said first rectifying means with said control device and said relay to energize said relay with said first rectified signal to open said normally closed contact and disconnect said output means from said input means when said first rectified signal exceeds a predetermined level determined by said second rectified signal.
Claim 3
Dependent Claim
18 words
A loudspeaker protection circuit according to claim 1, wherein said control device comprises a Darlington pair of transistors.
Claim 4
Dependent Claim
15 words
A loudspeaker protection circuit according to claim 1, wherein said control device comprises a thyristor.
Claim 5
Dependent Claim
45 words
A loudspeaker protection circuit according to claim 1, wherein said second rectifying means comprises means for adjusting the amplitude of the second rectified signal relative to the input signal to control the predetermined level of said first rectified signal at which said relay is energized.
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) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |