CN1812653B

CN1812653B - Variable impedance and power loudspeaker and power amplification and control circuit thereof

Info

Publication number: CN1812653B
Application number: CN 200510136496
Authority: CN
Inventors: 颜怀伟; 颜怀玮
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-12-29
Filing date: 2005-12-29
Publication date: 2011-12-07
Anticipated expiration: 2025-12-29
Also published as: CN1812653A

Abstract

The invention relates to a variable impedance and power loudspeaker and control circuit, orderly composed of loudspeaker and audio control switch, stopping and audio output capacitor, diode, power amplifier tube with collector and emitter as well as base resistor, input control switch of audio signal and input capacitor of audio signal thereof in electric connection; the invention can easily and freely switch as telephone receiver or loudspeaker mode and has advantages of ultrathin, ultralight, ultrasmall as well as high sensitivity, high effectivity and high output power as well as good tone quality and small distortion; the advantages provide maximum convenient for realizing thin and light of product and satisfying the demand of easily and freely switching telephone receiver or loudspeaker mode or the like usability for consumer, and avoid the harm of increasing radiation in headset and trouble and inconvenient for using headset. The invention can be extensive used in the laptop, sounding electronic dictionary or the like thin, light, small and high tone quality electronic field and the product thereof.

Description

Impedance and power variable formula loud speaker and power amplifier and control circuit

Because of the telephone set of the convenience of telephone set hand-free function, production and marketing manufacturer production and marketing at present all is with hand-free function basically, simultaneously, be receiver for different needs such as maintain secrecy must keep the sounding components and parts again.Traditional hand-free function mainly is to realize with corresponding power driving amplifier by installing sounding components and parts loud speaker additional, this has just increased loud speaker and weight thereof and its shared area and volume inevitably, equally also make machine volume inevitably, weight, (fact all proves with experience reliability repeatedly: under the identical prerequisite of other condition, failure rate often always becomes high-positive correlation with the number of component number) and design and the corresponding increase with difficulty of manufacturing cost, especially in the face of more and more miniaturization, ultra-thinization, the development of ultralightization and consumer market demand general trend then more demonstrate most important property such as its market competitiveness height.Receiver generally all is that impedance is very high for loud speaker, the sounding components and parts that power is very little, therefore it is difficult to replace loud speaker and function thereof, and because of the impedance height carefully makes the D.C. resistance of its coil very big with line, adding because of high impedance makes power output very low, these factors add makes its power consumption and heating also just inevitable equally very big together, so its energy utilization efficiency is very low, especially for being extensive use of, the mobile phone that quantity is extremely huge and other audio communication equipment, energy utilization efficiency is low just to be meaned must strengthen and transmits and receives power, and this just increases amount of electromagnetic radiation inevitably, particularly to the bigger electromagnetic radiation intensity of human body harm; There is a kind of wide-spread and what is called of using to replace the receiver of nearly body to reach reducing IVR equipment to comprise that mobile phone is the amount of radiation of mobile phone and intensity and to the extent of injury of human body with ear (plug) machine, actually this is not so, this way only can be strengthened but not weaken electromagnetic pollution and harm to human body and surrounding enviroment, because connect between the resistance of the electric wire of earphone and earphone voice coil loudspeaker voice coil winding and they, comprise and this machine between distributed capacitance (amount) between formed mutually one and/or a plurality of new be equivalent to the capacitance-resistance coupling and with the electromagnetic wave repeat transmitted and the receiver of induction type, promptly this moment, earphone and on line thereof were served as the antenna of strengthening propagating electromagnetic radiation, and it is more much longer than airborne antenna, the scope of laying is much also wide, the scope and the intensity of electromagnetic radiation has just been strengthened in the stack of these factors greatly, and the harm nature is just bigger wider than nearly body earphone; Also has a kind of same wide-spread and use, even ratio increase earphone is exactly to increase so-called radiation proof pad pasting to reach the electromagnetic radiation and harm purpose that weakens audio communication equipment such as mobile phone widely, this also is a kind of real erroneous tendancy that can realize that is difficult in fact, because detecting, many authoritys fact proved that most so-called radiation proof pad pastings or other so-called protection film substantially do not possess radiation protection ability, seldom even at all can not alleviate any radiation and energy thereof, even so, even if very can effectively alleviate radiation and harm, also transmitting and receiving signal strength signal intensity with sacrifice is cost, because can alleviate the means of radiation intensity mainly is nothing but shielding electromagnetic wave, this just must cause transmitting and receiving power with increasing is that cost is offset diaphragm to shielding electromagnetic waves, can't help consuming energy more, and the amount of electromagnetic radiation and the intensity that also can positive correlation ground increase human body because of the increase of amount of electromagnetic radiation and intensity are the extent of injury, also the increase because of power is significantly shortened battery life, the time that use each charging back also significantly shortens, even if reduce emission and received power to reduce electromagnetic hazard and pollution and battery consumption to improve directivity (the radio wave directivity is very strong), but this just makes that wireless audio communication device orientation is extremely strong, speech quality such as sound are suddenly big or suddenly small, smudgy, intermittent even conversation fault waits as broken string repeatedly functional reliability and other performance is greatly reduced, solution remain add high-power, so its harmful consequences is basic identical, and these factors also all can have a strong impact on the product market competition ability and serious increasing because of battery scrapped the increase of the environmental pollution that produces and use cost such as accelerating (battery of mobile phone is generally all more expensive, tens of at least even up to a hundred yuans); Increase loud speaker and can effectively reduce the electromagnetic radiation and the harm of and surrounding enviroment next to the shin, but have aforesaid such as increasing not enough problems such as components and parts and volume thereof, area, weight, cost to human body because of answering to die with respect to the remote-wireless that receiver is sayed.Obviously, innovation sounding components and parts that the low radiation hazard of the confidentiality of receiver and loud speaker if can be combined and be equipped with innovation and can (easily) control drive power amplifier, then it can not only effectively overcome the serial shortcoming of above-mentioned prior art and product, and its serial main advantages is that advantages such as the market share all are conspicuous all will finally be embodied in the market competitiveness especially.

Total be exactly impedance and power variable formula loud speaker and power amplifier and control circuit that the present invention designs for the serial problem that solves prior art and product for one goal of the invention, existing with principle, scheme and major advantage continue to introduce as after.The present invention directly utilizes receiver and the position that is had thereof, volume, area, weight with it, and get rid of and decide circle and vibrating diaphragm and iron core, change so that the vibrating diaphragm of direct sounding is integrated respectively but wire circle seldom is moving-coil and strong magnetic permanent-magnet alloy replaces, resistance is big by the superfine number of turns in line footpath is a lot of to change receiver, power consumption and heat production are all more decide circle generate an electromagnetic field earlier and magnetize iron core, the indirect sounding of vibrating diaphragm is inhaled, put to the suction, the thrust that are produced by the iron core after the magnetization again operation principle and pattern; Big and the little tonequality of integrated distortion is more true to nature and sensitivity is higher because of the moving-coil space, the number of turns few and easily increase line directly thus the resistance energy consumption and the heating littler, but it can bear and export very big audio power, not only solved receiver and decided circle little such as power, the energy consumption height, serious distortion even hoarse unpleasant to hear all difficult problems such as serious noise that the easy distortion of sound causes because of the vibrating membrane space is extremely limited when especially sound is big, also magnetic material just can obtain powerful permanent magnetic because of the superpower magnetic that adopts strong magnetic permanent-magnet alloy and have only needs seldom with same powerful magnetic reserve capability, make product of the present invention extremely easily do very for a short time, very light, very thin but its tonequality, power and sensitivity are but very excellent, thereby solved small-sized that existing product needs to be resolved hurrily, ultra-thin, ultralight, high-power and high tone quality, a serial difficult problem such as high sensitivity, be equipped with controlled easily (convenience) control power driving circuit again, just satisfactorily realized the present invention and goal of the invention thereof comprehensively for a total inventive concept.

Accompanying drawing and operation principle and advantage explanation:

Contrast accompanying drawing: Y is a loud speaker; V is the magnet of Y; Q is moving (sound) circle of Y, and B is for reinforcing the specially designed backplane level of Q; X is the hollow magnetic pole of Q; Z is that the vibrating membrane of Y is a sounding body; P is that the fixed support of Z is also used as outer magnetic pole; D is a diode; J is a power tube, and c is that output (current collection) utmost point of J, base stage, the e that b is J are the emitter of J; K ₁Be audio signal input control switch, K ₁', K ₁" be respectively the end of K1; K ₂, K ₃Be respectively two group winding FF ' and the audio input end F of GG ' and the control switch of G of the coil M of Q; C ₁Be the audio frequency input capacitor; C ₂For every direct sum audio frequency output capacitor; R ₁Be power tube J base stage b (biasing circuit, electric current) resistor; R ₂Power supply and loading resistor for c; R ₃Resistor for the working point of the path of e and stable J.

C ₂An end and K ₂-K ₅An end be electrically connected, C ₂The other end and negative pole and c and the R of D ₂An end be electrically connected K ₂-K ₃The other end be electrically connected respectively with own corresponding F-G end, each end of F '-G ' is direct with power supply-it is ground connection that (bearing) utmost point is electrically connected, the positive pole of D and K ₁An end K ₁' be electrically connected K ₁Other end K ₁" be electrically connected with b, K ₁With R ₁And C ₁An end be electrically connected R ₁And R ₂The other end and power supply+extremely be electrically connected C ₁The other end be electrically connected (omission), R with this machine audio-source output ₃An end and e be electrically connected, R ₃Other end ground connection.

the contrast accompanying drawing is further introduced structure, function and innovation advantage: loudspeaker Y is because adopting the permanent magnetism ferromagnetic material, so its magnet V does very thinly, magnetic core X also makes hollow type, this has just alleviated weight and volume greatly, in addition, therefore because of magnetic core be hollow type can use this space as lay moving-coil Q and activity space, also can further utilize the inner space of moving-coil that two windings of moving-coil all are produced on the inwall of moving-coil, this makes loudspeaker miniaturization more with regard to having saved again moving-coil and movable a lot of spaces that should separately account for thereof, moreover, but moving coil winding of the present invention is coil change traditional single line list around single group series connection for two-wire in the same way the two groups of spaced winding and can alone serial or parallel connection again etc. the independent winding of multiple usage and purposes be absolute coil, make every group of coil in, external diameter and weight and effective (namely produce and cut the magnetic line of force) line length with exert oneself size and the uniformity and resistance (comprising D.C. resistance and AC impedance) etc. with volume and increase power output and reduce that distortion namely improves the closely-related serial important indicator of tonequality (seeing below) and data are all accomplished highly consistent simultaneously, and these great shortcomings of traditional voice coil loudspeaker voice coil and too far behind to catch up just, (D.C. resistance reduces power output and generates heat because of direct power consumption as the D.C. resistance of its single coil and energy consumption thereof, the thing of even burning voice coil loudspeaker voice coil also happens occasionally, not rare, AC resistance is that impedance is not generally consumed energy and do not generated heat yet comparatively speaking) be only 1/2 of tradition series connection voice coil loudspeaker voice coil, all can only appoint one group of voice coil loudspeaker voice coil to reduce volume and economize on electricity to extend service time of battery and life-span under receiver or hands-free state when only needing small volume, voice coil loudspeaker voice coil D.C. resistance in parallel is only 1/4 of tradition series connection voice coil loudspeaker voice coil when the larger volume of needs, these are because the number of turns of each of two absolute coils and D.C. resistance only are 1/2 of its series coil, simultaneously be equivalent to strengthen one times of wire diameter because of parallel connection again, its D.C. resistance is reduced by half again, also can connect when needs utmost point amount of bass, this shows its adaptability, applicability and bag (holding concurrently) capacitive is very wide very strong, advantage is really more also important, because these are the major function of most audio communication instruments and the place of use value just, the 4th, not only make coil diameter increasing and direction also outside because expanding, Magnetic Core Design is become the hollow magnetic core and moving-coil is designed to inner ring and corresponding internal layer winding thereof, particularly inner ring of the present invention is attached on the voice coil loudspeaker voice coil inboard wall of skeleton because of coil, can be difficult to by the protective effect of the voice coil loudspeaker voice coil outer wall without winding rub with magnetic core, unless the degree that friction seriously all is worn through to outer wall, and the probability that this possibility namely occurs is very little, but also in voice coil loudspeaker voice coil bottom, do in addition one approximately the backplane level B of 0.1-1mm Bao Kehou to strengthen support force, in adding that the direct firmly splicing of voice coil loudspeaker voice coil top and vibrating membrane is even incited somebody to action, external form voice coil loudspeaker voice coil and vibrating membrane be being made of one and strong resistance to deformation directly, these are also the serial important particular advantages that the present invention just may have, therefore can prevent effectively that the real core magnetic core of magnetic seam loudspeaker that common traditional double-deck magnetic pole forms is because of moving-coil coil long-term motion and heating or the dilatancy and because of fastener such as the screw nail of collision or fixing double-deck magnetic pole or binding agent is as loosening in glue makes double-deck magnetic pole produce displacement of making moist, make the friction of coil and magnetic core and the powerful noise of the little distortion of sound and generation after coil covering (because of the enamel-covered wire enamelled coating very thin and descended by thermal softening or sex change such as adhesive force even to break to wait very easy to be very fast) is by the magnetic core worn-off] or dual-purpose space operation formula, distortion and displacement and adverse consequences thereof have not only effectively been prevented, weight and/or volume have also effectively been alleviated, and efficient (especially inside and outside dual-purpose formula can twice utilization and change permanent magnetic force be sounding power) have utilized internal magnetic field power and density of line of magnetic force far above outside, magnetic induction intensity is also far above the magnetic signature of outside, even this only can produce weak alternating magnetic field and magnetic force with regard to making moving-coil only pass to light current, (same polarity magnetic force repels each other but it is in the powerful constant permanent magnetic interaction with the permanent magnet generation, the coupling of heteropolarity magnetic force) time, also can produce same powerful suction to it because of powerful permanent magnetic force, repulsion and enlarged markedly the active force of (being equal to amplification), thereby strengthened the movable energy of moving-coil, the energy that its vibrating membrane that promotes to be bonded as one with it is sounding body Z is also grown simultaneously, that is less alternating magnetic field (power) can be by means of stronger permanent magnetic force, only need take consume less sounding power as cost just can be at an easy rate will the permanent magnetic force of part the strength portion of energy that also convert the required consumption of sounding to namely promote voice coil loudspeaker voice coil and the moving kinetic energy of vibrating membrane fortune (shaking) and further be converted into therefrom to promote air to transport kinetic energy that (shaking) move be the acoustic energy of sounding, thereby available less input power also can obtain larger volume, that is increased the power output of moving-coil, that is to say that less alternation magnetic force can be amplified by stronger permanent magnetic force, therefore available less input power obtains larger power output and can make further frivolous small-sized and high-qualityization of loudspeaker of the present invention and power driving circuit and corresponding components and parts thereof, the electric energy and the caloric value that consume are also less because of the increase of power output according to the law of conservation of energy principle, thereby significantly reduce and receive, send out power and caloric value and battery and power consumption and environmental pollution and use cost, as the sounding input power because of only need be less, just make and only need very little audio frequency input signal just can reach the conversation purpose, be equivalent to improve machine sensitivity and speech quality as reducing converse directionality and broken string etc., this just can make emission and received power all can two-wayly reduce, mean be no matter quantity and the transmitting power of cell site and transmitter thereof or receiving equipment namely with it the transmitting-receiving power of corresponding IVR receiving equipment can two-wayly reduce, fixing (holder) frame P of the vibrating membrane Z of loudspeaker Y and voice coil loudspeaker voice coil Q makes with magnet with wide and parallel, and because of its with magnet with wide and parallel, again that using with magnet is that the identical permanent-magnet material of hollow magnetic core is made and with the powerful permanent magnetic force of tool, therefore be also used as outer magnetic pole and invigoration effect permanent magnetic force and the effect in moving-coil, the magnetic force strengthening effect extremely significantly also further makes the frivolous miniaturization of loudspeaker, thereby make the whole volume and weight of loudspeaker reduce to bottom line, these favorable factors all further reduce the volume of the mobile phone of the especially extensive production and marketing use of complete machine more effectively, weight, caloric value and energy resource consumption and environmental pollution and use cost, receipts as extending battery life and minimizing cell site's quantity and (transmitting power) scale and emission and receiving equipment, send out the environmental pollutions such as the electromagnetic hazard to human body that power etc. causes and refuse battery quantity, and reduce the battery power consumption and extend the battery stand-by time that (frivolous miniaturization is fundamental mark with improving the market competitiveness, and lower calorific value is frivolous small-sized basic prerequisite) etc. serial great advantage, the acting as of diode D make when using the receiver function the less audio signal of energy utilize its forward on state characteristic with direct input loudspeaker, make it only can send faint sound only to need the small volume characteristics to be fit to receiver, loudspeaker replaced and served as receiver and use and bring into play the corresponding function of receiver this moment, and no matter loudspeaker be do receiver or hands-free with the time diode D can automatically utilize again self very big anti-phase resistance to block power amplifier tube J to export (current collection) utmost point c and power supply and load resistance R₂The direct current reverse pumping to K switch₁', also just having avoided the prime audio signal source is C₁And line because of with K₁Even ' too near and induction that easily cause when loudspeaker is done hands-free the use and through power tube the distortion whistle after reflex is amplified repeatedly etc. interference, but loudspeaker when the receiver state because of base stage b without bias current, not conducting of J, its c utmost point and R₂Though upper have the direct current pressure drop but without electric current and power or direction, change, namely without alternating signal, produce, therefore also without C₁Induction problem is namely noiseless, the positive terminal of D with every straight (stream power supply) capacitor C₂An end be electrically connected to, its negative pole end inputs gauge tap K with audio signal₁An end K₁' be electrically connected to, so that the input channel of the loudspeaker audio frequency power supply under the receiver state to be provided; C₂Can isolate simultaneously R₁And R₂Equal not identical direct current pressure drop and the DC currents of generation and character and effect respectively, to avoid moving-coil also because of by these direct currents and produce that permanent-magnetic field power is resisted and the i.e. reduced side effects such as " demagnetizations " or destroy loudspeaker and comprise the performances such as tonequality and volume, K of the magnetic that weakens the loudspeaker permanent-magnet material₂-K ₃Effect be further to regulate and control tonequality, volume or quiet, also regulated and controled when volume because of regulation and control vibrating membrane vibration position, intensity and amplitude Effective Regulation tonequality: when each key is all closed the volume maximum, while all opening be quiet, the rest may be inferred, the traditional approach of reduction input audio signal intensity that so just can be by routine regulates and controls tonequality, volume, thereby reduce noise, improves signal to noise ratio and namely improves tonequality; K₂-K ₃Also can to adopt variable resistor be potentiometer is regulated to gradual change type with the transition formula volume tonequality that becomes switch and regulates and controls continuously, and no matter is to adopt switch or potentiometer regulation and control all more reliable, convenient and simple than the loaded down with trivial details perishable integrated chip computing circuit of complexity and regulation and control; C₂Another effect be regulation and control tonequality, by regulating C₂The capacitance size control the frequency high low range of the tone currents that passes through, due to C₂Also be C in when loudspeaker doubles as receiver and uses₁Tone currents path is provided, namely has been the total path that comprises power amplifier output tone currents, its capacitance is because considering that the large value of the electric current that passes through is generally than C₁For greatly, again because of C₂With C₁What form is series capacitance circuit and cut down C2 part capacitance, add at C₁And C₂Middle D in addition₂The DC internal resistance in number Europe-tens of Europe is to from C₁The attenuation of certain amplitude of tone currents of upper frequency, therefore be easy to by suitable adjustment C₂(actual measurement is about C₁The 3-10 of capacity is doubly) capacity just can the compatible C of fine realization₁Frequency characteristic is overall tonequality balance; Pass through K₁Connecting and disconnecting R₁Be electrically connected to change the permanent fixedly electrical connection pattern of traditional bias current with the bias current of b, therefore not only can ensure aforesaid when with receiver the power tube base stage because of be cut off without bias current do not produce noise jamming receiver tonequality, also can ensure when loudspeaker replace receiver with the time provide the power tube bias current to reduce distortion to improve tonequality, e by series connection with it stable operating point and doublely do little resistance (generally the being about 0.5-1 Europe) resistance R that protector is used₃Ground connection, to form audio frequency alternating current circuit loop.

Embodiment and operation principle of the present invention and advantage supplementary notes: contrast accompanying drawing, loud speaker Y is because of adopting the permanent magnetism ferromagnetic material, so its magnet V and magnetic core X all do very thinly, general 0.2-0.5cm in addition more (surpass) thin promptly enough, magnetic core X makes hollow type and will move the unsettled the top that is placed in magnetic core of (sound) circle Q is the magnetic pole place, the moving-coil wall is to keep 0.1-0.2mm intermittently to be advisable with magnet core wall, because have only the magnetic line of force at magnetic pole place the most concentrated, the die magnetic force of density is the most powerful, the degree of depth of laying topmost flushes on the plane with magnetic core substantially with facial planes in the voice coil loudspeaker voice coil winding, to ensure the voice coil loudspeaker voice coil Shi Douke cutting magnetic line and produce the maximum promotion vibrating membrane i.e. power of vibration that is synchronized with the movement to greatest extent that no matter moves up and down, thereby obtaining the maximal audio power output is max volume, the shape of vibrating membrane can be a matrix, convex, plane, round, square type or other Any shape or its combined shaped all can, present embodiment is that further conserve space adopts plane, but this to be not the present invention can only adopt planar shaped (down with); Diode D with power greater than the silicon of 0.1W, withstand voltage any kind greater than 6V or germanium diode all can, present embodiment adopts good and cheap and the most widely used 1N4004 and 1N4007 etc.; Power tube J with power greater than the PNP of 0.3W, withstand voltage any kind greater than 20V or NPN pipe all can, accompanying drawing adopts 0.5-1W, withstand voltage 25-50V NPN type, gets final product as adopting the positive-negative-positive power supply polarity being opposite with the NPN type; Audio signal input control switch K ₁With the two group switches of the miniature hilted broadsword of any kind such as press-key lock fixed pattern, dial type, Electronic Control as touch or press-type etc. all can, present embodiment adopts push type, use operating maintenance etc. more simple and convenient; With K ₁As a same reason, voice coil loudspeaker voice coil K switch ₂-K ₃Also with miniature press-key lock fixed pattern but use hilted broadsword simply connected formula instead and get final product; Capacitor C ₁With the non-polar condenser of capacity greater than 0.1 μ F, withstand voltage 6-10 volt, present embodiment adopts 0.3 μ F6.3 volt; Capacitor C ₂With capacity greater than the nonpolarity or electrolytic capacitor of 1 μ F all can, present embodiment adopts 10 μ F10 volt electrolytic capacitor; R ₁And R ₂Resistance with the difference at double of concrete power tube J and parameter such as multiplication factor etc. and mains voltage variations broad, obviously also just can not be in advance in concrete mode such as embodiment and stipulate its occurrence, so state reference value R ₁200 Europe-20K and R ₂20 Europe-2K use only for reference, but this does not influence the described those skilled in the art of Patent Law at all and implements this patent, because at the selected back of concrete power tube, its product description or consult reference book such as handbook and all can obtain every accurately concrete parameter, to make parameter reach optimum range also be the most basic prerequisite general knowledge and test a large amount of and commonly used is arranged equally and the detailed introduction of method of adjustment and reference book, product description etc. and record and belong to general knowledge together to adjust resistance value; As previously mentioned, because of R ₃Function mainly be stable operating point and serve as insurance (resistance) thread, and the promptly in most cases little in normal operation big variation of these functions, so it is less demanding to accuracy and accuracy, in most cases resistance is all very suitable in the interval in 0.5-2 Europe, too low stability and safety effect is poor, too high important parameters such as amplifying power influence to loud speaker and the power tube power output and the latter is bigger; All the other situations and accompanying drawing and explanation thereof, advantage are introduced similar, no longer repeat superfluous stating.

The present invention also has following serial main advantages: receiver and loud speaker and function thereof and energy freely switch and pole switching is convenient freely because of integrating, can switch to receiver or loud speaker mode at any time arbitrarily and need not dropped calls, single loud speaker double as receiver and ultra-thin, ultralight, subminaturization (can do also little also gently also thin more a lot) and high sensitivity than receiver earphone, high effect and high-output power and tonequality grace, serial great innovation of the little grade of distortion and advantage, these advantages are for realization and satisfy the frivolous miniaturization of product, especially melodious grace of tonequality and consumer's needs at any time and likes and freely select arbitrarily to converse and the crucial serviceability and the consumption demand aspect of many decision market shares such as Music Appreciation mode provide very big convenience and competitiveness, as be beneficial to and correct so-called ear (plug) machine and alleviate radiation and reach erroneous tendancies such as harm to the user, not only bother inconvenience because of using earphone as described above, and it is real for having increased radiation and harmfulness.The present invention integrates above-mentioned serial main advantages, so tool applications well and market prospects, as except that the above and mobile phone etc. require the frivolous small-sized low energy consumption lower calorific value application, such as wide too with the application in frivolous small-sized high tone quality electronic applications such as the notebook computer in the huge market of tool, sounding electronic dictionary and the product with mobile phone.

Claims

1. impedance and power variable formula loud speaker, its feature is as follows: ferromagnetism alloy permanent magnet connects and fixedly vibrating membrane fixed support and hollow magnetic core; The vibrating membrane fixed support connects and fixing vibrating membrane, and the outer magnetic pole of double as hollow magnetic core; The hollow magnetic core is made of inside and outside magnetic pole, built-in double-winding voice-coil; Vibrating membrane connects and fixing double-winding voice-coil; Double-winding voice-coil is double-wire spaced, separate; The inside and outside wall single layer winding of double-winding voice-coil, the bottom connects and is fixed with backplane level, and the double winding of voice coil loudspeaker voice coil uses inside and outside magnetic pole simultaneously.

2. the power amplifier and the control circuit of described impedance of claim 1 and power variable formula loud speaker, its feature is as follows: every direct sum audio frequency output capacitor C ₂An end and audio frequency input control switch K ₂, K ₃An end be electrically connected, every direct sum audio frequency output capacitor C ₂The other end be connected with the negative electricity of diode D, the negative pole of diode D is electrically connected with the collector electrode c of power tube J, collector electrode c and the resistor R of power tube J ₂An end be electrically connected resistor R ₂The other end be electrically connected audio frequency input control switch K with positive source ₂, K ₃The other end respectively with the two group winding FF ' of the coil M of the moving-coil Q of own corresponding loud speaker Y and audio input end F, the G electrical connection of GG ', the two group winding FF ' of the coil M of the moving-coil Q of loud speaker Y and audio output F ', the G ' ground connection of GG ', the positive pole of diode D and audio frequency input control switch K ₁An end K _{1 '}Be electrically connected audio frequency input control switch K ₁Other end K _{1 "}Be electrically connected audio frequency input control switch K with the base stage b of power tube J ₁With resistor R ₁An end be electrically connected audio frequency input capacitor C ₁An end and resistor R ₁An end be electrically connected resistor R ₁The other end be electrically connected audio frequency input capacitor C with positive source ₁The other end be electrically connected the emitter e of power tube J and resistor R with this machine audio-source output ₃An end be electrically connected resistor R ₃Other end ground connection.