GB1407824A - Overload protection circuit for loudspeakers - Google Patents
Overload protection circuit for loudspeakersInfo
- Publication number
- GB1407824A GB1407824A GB3913672A GB3913672A GB1407824A GB 1407824 A GB1407824 A GB 1407824A GB 3913672 A GB3913672 A GB 3913672A GB 3913672 A GB3913672 A GB 3913672A GB 1407824 A GB1407824 A GB 1407824A
- Authority
- GB
- United Kingdom
- Prior art keywords
- resistor
- relay
- parallel
- series
- thermistor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/007—Protection circuits for transducers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/085—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current making use of a thermal sensor, e.g. thermistor, heated by the excess current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/041—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature additionally responsive to excess current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H6/00—Emergency protective circuit arrangements responsive to undesired changes from normal non-electric working conditions using simulators of the apparatus being protected, e.g. using thermal images
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Emergency Protection Circuit Devices (AREA)
- Amplifiers (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
1407824 Protective arrangements ELEKTKOAKUSZTIKAI GYAR 22 Aug 1972 [7 April 1972] 39136/72 Heading H2K [Also in Division H4] A loudspeaker overload protection circuit responsive to reel power averaged over a period of time utilizes an indirectly heated thermistor, (Fig. 5). A rectifier D and capacitor C 1 are in series between input terminals A, B. Also connected across the input terminals A, B are a loudspeaker H and a pair of back contacts of a relay. The relay winding J 1 is in parallel with the capacitor C 1 while the indirectly heated thermistor TK 1 is in series with the relay winding J 1 and in parallel with the capacitor C 1 . A Zener diode Z 1 in parallel with the capacitor C 1 operates in the Zener direction. A filament winding of the thermistor TK 1 is connected in series with a resistor R 2 to the input terminals A, B. The Zener voltage is preferably about 10% below the voltage at which relay J 1 operates. Operation of the protection circuit depends on the heating up time of thermistor TK 1 and this is a function of current flowing in its filament and of the ambient temperature. A resistor R 3 in parallel with the thermistor TK 1 may be omitted, (Fig. 4, not shown), but, if present, prevents unwanted current flow through thermistor TK 1 , permitting greater safety and accuracy while preventing self heating of the thermistor TK 1 thereby giving it a longer life. An even simpler circuit (Fig. 3, not shown) replaces the full wave rectifier D with a half wave rectifier. To take account of frequency dependant heating up of the loudspeaker coil the resistor R 2 of Fig. 5 may be replaced by a complex impedance (Z 2 ), Fig. 7, (not shown), e.g. an inductance and resistor in parallel, with both in series with a further resistor. Alternatively, a complex impedance (Z 2 #, Fig. 8 (not shown), formed of an inductance, capacitor and resistor in parallel and, in series with these, another resistance, may be placed in parallel with the thermistor TK 1 . To ensure that after overload conditions cease the operating condition is restored without undue delay there may be provided, in parallel with relay # 1 , a capacitor (C 2 ) not shown, the parallel circuit of relay # 1 and capacitor (C 2 ) being connected in series with a further resistor (R 5 ), not shown. This resistor (R 5 ) is connected in parallel with a further pair of back contacts of relay # 1 . Alternatively three back contacts may be omitted. The resistor (R 5 ) may be a voltage dependent resistor. In another alternative arrangement the resistor R 1 is a voltage dependent resistor, or a voltage dependent resistor in series with a resistor of constant value is substituted for resistor R 1 . An alternative circuit (Fig. 10) has a diode D 2 operating in the forward direction. If overload conditions occur, current flow through diode D 2 rises rapidly and the potential built up on the poles of the diode D 2 is applied to a pulse inverter acting as a logical NO circuit. The pulse inverter is arranged to operate a relay J 2 before the relay J 1 operates. Relay J 2 is used to signal overload on the loadspeaker so that remedial action may be taken before relay J 1 disconnects the loudspeaker H. A resistor R 4 , Fig. 12, in series with the diode D 2 shortens the time between operation of relay J 2 and J 1 . Fig. 12 shows an elaboration of the circuit of Fig. 10 in which two loudspeakers H, H<SP>1</SP> are used, (e.g. a tweeter and woofer), and are controlled using a single voltage stabilizing Zener diode Z 1 . Overload of either loudspeaker cuts off both loudspeakers. The circuit including the phase inverter provides early warning of overload.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
HUEE002018 HU164736B (en) | 1972-04-07 | 1972-04-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1407824A true GB1407824A (en) | 1975-09-24 |
Family
ID=10995436
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB3913672A Expired GB1407824A (en) | 1972-04-07 | 1972-08-22 | Overload protection circuit for loudspeakers |
Country Status (12)
Country | Link |
---|---|
AT (1) | AT320767B (en) |
BG (1) | BG26825A3 (en) |
CA (1) | CA970697A (en) |
CS (1) | CS171737B2 (en) |
DD (1) | DD98184A5 (en) |
DE (1) | DE2241266C3 (en) |
FR (1) | FR2178849B1 (en) |
GB (1) | GB1407824A (en) |
HU (1) | HU164736B (en) |
PL (1) | PL79698B1 (en) |
SE (1) | SE382545B (en) |
SU (1) | SU513653A3 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2624252A1 (en) * | 1976-05-29 | 1977-12-01 | Rudolf Goebel | OVERLOAD PROTECTION CIRCUIT FOR SPEAKER ARRANGEMENT |
WO1980002477A1 (en) * | 1979-05-08 | 1980-11-13 | Fortieth Benelux Nominees Pty | Protection device or circuit for loudspeakers |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3644288A1 (en) * | 1986-12-23 | 1988-07-07 | Hans Deutsch Akustikforschung | Overload protection circuit |
-
1972
- 1972-04-07 HU HUEE002018 patent/HU164736B/hu not_active IP Right Cessation
- 1972-08-22 GB GB3913672A patent/GB1407824A/en not_active Expired
- 1972-08-22 AT AT722972A patent/AT320767B/en not_active IP Right Cessation
- 1972-08-22 DE DE19722241266 patent/DE2241266C3/en not_active Expired
- 1972-08-23 CA CA150,288A patent/CA970697A/en not_active Expired
- 1972-08-25 DD DD16525772A patent/DD98184A5/xx unknown
- 1972-10-12 SE SE1317772A patent/SE382545B/en unknown
- 1972-10-16 CS CS694272A patent/CS171737B2/cs unknown
- 1972-10-18 BG BG2165572A patent/BG26825A3/xx unknown
- 1972-11-20 FR FR7241211A patent/FR2178849B1/fr not_active Expired
- 1972-11-22 PL PL15899072A patent/PL79698B1/en unknown
-
1973
- 1973-01-29 SU SU1878741A patent/SU513653A3/en active
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2624252A1 (en) * | 1976-05-29 | 1977-12-01 | Rudolf Goebel | OVERLOAD PROTECTION CIRCUIT FOR SPEAKER ARRANGEMENT |
WO1980002477A1 (en) * | 1979-05-08 | 1980-11-13 | Fortieth Benelux Nominees Pty | Protection device or circuit for loudspeakers |
Also Published As
Publication number | Publication date |
---|---|
CA970697A (en) | 1975-07-08 |
DE2241266C3 (en) | 1980-02-14 |
DE2241266A1 (en) | 1973-10-18 |
CS171737B2 (en) | 1976-10-29 |
DD98184A5 (en) | 1973-06-05 |
DE2241266B2 (en) | 1979-06-21 |
FR2178849B1 (en) | 1980-04-18 |
SE382545B (en) | 1976-02-02 |
PL79698B1 (en) | 1975-06-30 |
BG26825A3 (en) | 1979-06-12 |
FR2178849A1 (en) | 1973-11-16 |
AT320767B (en) | 1975-02-25 |
HU164736B (en) | 1974-04-11 |
SU513653A3 (en) | 1976-05-05 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |