CN202103846U - High-performance hearing aid made by discrete components - Google Patents

Abstract

The utility model belongs to the fields of electronic technique and low-frequency signal amplification, and provides a high-performance hearing aid made by discrete components. The hearing aid comprises a direct current power supply DC, a sound wave signal conversion circuit, a front low-frequency amplification circuit, a volume adjusting circuit, and a power amplification circuit, and is characterized in that a PNP triode VT3 in the power amplification circuit is connected in an emitter electrode output form, and an earphone socket CZ with a normally-open contact is connected to the output load loop of the PNP triode VT3. The hearing aid does not need application-specific integrated circuits which are relatively high in price, and the discrete components are competent for designing and making the hearing aid. The hearing aid has the characteristics of simple circuit structure, few peripheral components, wide working voltage scope, low quiescent current, low electricity consumption, small distortion, good tone quality, and the like. The output power of the hearing aid can meet the requirement of people having obstacle in hearing, and the hearing aid solves or makes up the problems that some brand-name hearing aids on the market are high in price, difficult in popularization, and the like.

Description

The high-performance hearing aids that discrete component is made

Technical field

The utility model belongs to electronic technology and low frequency signal amplification sector, is the high-performance hearing aids of making about a kind of discrete component.

Background technology

How hearing aids on the market is made with special-purpose integrated amplifier circuit design now, and the integrated circuit peripheral cell in its circuit is more, and circuit structure is comparatively complicated, and the market price is more expensive.The utility model is described to be the high-performance hearing aids made from discrete component, and it comes down to a kind of low-frequency signal amplifier.Very many years ago, because the quality and the performance of germanium transistor all do not pass a test,, often adopt the amplifier element of the high frequency transistor of germanium material as circuit so make hearing aids in order to obtain reasonable signal amplification effect.Nowadays the quality of element and performance are not problem already, make hearing aids and need not the more expensive application-specific integrated circuit (ASIC) of price at all, select for use discrete component just to design and produce and can be competent at.Characteristics such as that the circuit of the utility model has is simple in structure, peripheral cell is few and operating voltage range is wide, quiescent current is little, little power consumption, distortion is little and tonequality is good.Its power output can satisfy the requirement that the sense of hearing has the obstacle people fully, can improve the aged's hearing, also can bring help to teen-age learning and memory, and solving or remedied on the market, there is the price height in some brand hearing aids, be difficult for shortcoming such as universal.

Specify related relevant technologies content in the high-performance hearing aids manufacturing process that this discrete component makes below.

The utility model content

Goal of the invention and beneficial effect: the high-performance hearing aids that the described discrete component of the utility model is made need not the more expensive application-specific integrated circuit (ASIC) of price, selects for use discrete component just to design and produce and can be competent at.The utlity model has that circuit structure is simple, peripheral cell is few and operating voltage range is wide, quiescent current is little, little power consumption, characteristics such as distortion is little and tonequality is good.Its power output can satisfy the requirement that the sense of hearing has the obstacle people, can improve the aged's the sense of hearing, also can bring help to teen-age learning and memory, and solving or remedied on the market, there is the price height in some brand hearing aids, be difficult for problems such as universal.

Technical scheme: the high-performance hearing aids that discrete component is made is made up of DC power supply DC, acoustic signals change-over circuit, preposition low-frequency amplifier circuit, volume control circuit, power amplification circuit; It is characterized in that: the PNP triode VT3 in the power amplification circuit is connected into the emitter output form, is connected to the earphone socket CZ of band normally opened contact in the output loading loop of PNP triode VT3.

Connection features in the each several part circuit between the components and parts

The characteristic of acoustic signals change-over circuit is: the audio signal output pin of Electret condenser microphone MIC links to each other with the positive pole of an end of resistance R 1, electrochemical capacitor C1, the anodal VCC of the other end connection circuit of resistance R 1, the metal shell termination circuit ground GND of Electret condenser microphone MIC.

The characteristic of preposition low-frequency amplifier circuit is: the base stage of NPN triode VT1 connects the negative pole of electrochemical capacitor C1 and an end of resistance R 2; The other end of the collector electrode connecting resistance R2 of NPN triode VT1 and an end of resistance R 3 and the positive pole of electrochemical capacitor C2, the emitter connection circuit ground GND of NPN triode VT1.

The characteristic of volume control circuit is: the negative pole of the termination electrochemical capacitor C2 of potentiometer RP, the positive pole of the lever arm termination electrochemical capacitor C3 of potentiometer RP, the other end connection circuit ground GND of potentiometer RP.

The characteristic of power amplification circuit is: the base stage of NPN triode VT2 connects the end of the negative pole of electrochemical capacitor C3, negative feedback resistor R5; The collector electrode of NPN triode VT2 connects an end of base stage and the resistance R 4 of PNP triode VT3; The anodal VCC of the other end connection circuit of resistance R 4; The emitter connection circuit ground GND of NPN triode VT2, the pedestal end of the emitter lug machine transplanting of rice seat CZ of PNP triode VT3 and the other end of negative feedback resistor R5, the collector electrode connection circuit ground GND of PNP triode VT3.

The connection features of earphone socket CZ is: the emitter of the pedestal termination PNP triode VT3 of earphone socket CZ, and the anodal VCC of the fixed contact connection circuit of earphone socket CZ, the moving contact of earphone socket CZ connects the positive pole of DC power supply DC.

The circuit working principle: in the accompanying drawing circuit by DC power supply, Electret condenser microphone, prepositionly lowly put, volume control circuit, power amplification circuit and insert earphone form.

Electret condenser microphone MIC makes transducer; It converts acoustic signals into audio signal; And deliver to preposition low-frequency amplifier circuit through coupling capacitance C1 and amplify, resistance R 1 is the biasing resistor of Electret condenser microphone MIC, for giving the Electret condenser microphone operate as normal bias voltage is provided.

Entire circuit comes down to a multistage audio frequency amplifier that is made up of triode VT1～VT3.NPN triode VT1, resistance R 2, resistance R 3 are formed preposition low-frequency amplifier circuit, will contain the audio signal of coming through the C1 coupling and carry out preposition amplification, and the audio signal after the amplification is added on the potentiometer RP through electrochemical capacitor C2, and potentiometer RP is used for regulating volume.NPN triode VT2, PNP triode VT3 form power amplification circuit, and PNP triode VT3 is connected into the emitter output form, and resistance R 5 plays negative feedback, are mainly the tonequality of stablizing and improve audio signal of circuit working.Audio signal is through after the power amplification, and its output impedance is lower, promotes 16 Ω low-resistance insert earphone work through earphone socket CZ.

Description of drawings

Accompanying drawing is the embodiment circuit working schematic diagram that the utility model provides the high-performance hearing aids of a discrete component making; For reducing the interference of electromagnetic signal, require the metal shell termination circuit ground GND of Electret condenser microphone MIC to Electret condenser microphone MIC.

Embodiment

The circuit working schematic diagram of the high-performance hearing aids of making according to discrete component shown in the accompanying drawing and the components and parts specification requirement of description of drawings and the following stated are implemented, and can realize the utility model.

The selection of components and parts and technical parameter thereof

Electret condenser microphone MIC should select two ends output type Electret condenser microphone for use, and its drain D is the audio signal output pin, connection circuit ground GND after the metal shell end of Electret condenser microphone links to each other with source S.It is output that FET is connected into drain D, and its output signal has certain voltage gain, can make the remolding sensitivity of Electret condenser microphone higher.

Electret condenser microphone MIC select for use the CM-18W type (the high sensitivity Electret condenser microphone of φ 10mm * 6.5mm), its sensitivity is divided into five retainings, representes with color dot respectively: redly be-66dB, Xiao Huang be-62dB, rheum officinale is-58dB, Lan Sewei-54dB is white greater than-52dB; Present embodiment is selected the product of white point for use.

VT1, VT2 adopt models such as NPN triode 2SC9014, and VT3 adopts models such as PNP triode 2SC9012, requires 3 transistorized multiplication factor β >=100;

Resistance uses RTX-1/16W type metalfilmresistor, the resistance 5.1K Ω of resistance R 1, the resistance 100K Ω of resistance R 2; Resistance 820 Ω of the resistance 1.5K Ω of resistance R 3, resistance R 4, the resistance 180K Ω of resistance R 5; RP selects solid potentiometer for use, and its resistance is 10K Ω;

C1 selects electric capacity of the dacron for use, and its capacity is respectively 0.22 μ F;

C2～C3 selects the withstand voltage electrochemical capacitor of 16V that is, capacity all is 47 μ F;

Insert earphone is selected the moving-coil type insert earphone for use, and the impedance of insert earphone is 16 Ω, selects for use the impedance of insert earphone more little, and the power of audio frequency output is big more, but tonequality slightly reduces.

Circuit production and installation and debugging designing wiring and installation:

The installation of Electret condenser microphone MIC should be as much as possible away from power amplification circuit; The microphone lead-in wire is unsuitable long; And should adopt shielding conductor; Stop of the cause interference of level amplifying circuit in back, cause frequency distortion, even cause and utter long and high-pitched sounds otherwise cause easily that extraneous various noise signal is responded to lead-out wire to front stage circuits.

Conscientiously detect the performance of each components and parts, each components and parts all can not wrong, will notice that especially polarized component can not connect instead, as: triode, Electret condenser microphone and electrochemical capacitor etc.Guarantee the welding quality of components and parts, cut unnecessary lead-in wire after welding.

Circuit debugging: at first, through the resistance of adjustment resistance R 2, the collector current that makes NPN triode VT1 is about 1mA; Then, total quiescent current of test hearing aids gets final product about 6mA.Because of the parameter of the Electret condenser microphone MIC that uses is different, the resistance of R1 need be done suitable adjustment sometimes, should be transferred to that sound is clear, loud to be as the criterion; The negative feedback of resistance R 5 can be improved tonequality, and its resistance is more little, and to improve the effect of tonequality obvious more, but influences the power output of audio signal, and both take into account to note volume, tonequality in the debugging.

During use, hearing aids is placed in user's the coat pocket, notice that the sound hole that receives of Electret condenser microphone MIC should be outwardly.Put on insert earphone, and the insert earphone plug is inserted in the earphone socket CZ of hearing aids, circuit will be connected DC power supply DC automatically; Extract the insert earphone plug, hearing aids promptly cuts off the power supply automatically and quits work.

Claims (6)

1. the high-performance hearing aids made of a discrete component; Form by DC power supply DC, acoustic signals change-over circuit, preposition low-frequency amplifier circuit, volume control circuit, power amplification circuit; It is characterized in that: the PNP triode VT3 in the power amplification circuit is connected into the emitter output form, is connected to the earphone socket CZ of band normally opened contact in the output loading loop of PNP triode VT3.

2. the high-performance hearing aids that discrete component according to claim 1 is made; It is characterized in that: the audio signal output pin of the Electret condenser microphone MIC in the acoustic signals change-over circuit links to each other with the positive pole of an end of resistance R 1, electrochemical capacitor C1; The anodal VCC of the other end connection circuit of resistance R 1, the metal shell termination circuit ground GND of Electret condenser microphone MIC.

3. the high-performance hearing aids that discrete component according to claim 1 is made; It is characterized in that: the base stage of the NPN triode VT1 in the preposition low-frequency amplifier circuit connects the negative pole of electrochemical capacitor C1 and an end of resistance R 2; The other end of the collector electrode connecting resistance R2 of NPN triode VT1 and an end of resistance R 3 and the positive pole of electrochemical capacitor C2, the emitter connection circuit ground GND of NPN triode VT1.

4. the high-performance hearing aids that discrete component according to claim 1 is made; It is characterized in that: the negative pole of the termination electrochemical capacitor C2 of potentiometer RP in the volume control circuit; The positive pole of the lever arm termination electrochemical capacitor C3 of potentiometer RP, the other end connection circuit ground GND of potentiometer RP.

5. the high-performance hearing aids that discrete component according to claim 1 is made; It is characterized in that: the base stage of NPN triode VT2 connects the negative pole of electrochemical capacitor C3, the end of negative feedback resistor R5 in the power amplification circuit; The collector electrode of NPN triode VT2 connects an end of base stage and the resistance R 4 of PNP triode VT3; The anodal VCC of the other end connection circuit of resistance R 4; The emitter connection circuit ground GND of NPN triode VT2, the pedestal end of the emitter lug machine transplanting of rice seat CZ of PNP triode VT3 and the other end of negative feedback resistor R5, the collector electrode connection circuit ground GND of PNP triode VT3.

6. the high-performance hearing aids that discrete component according to claim 1 is made; It is characterized in that: the emitter of the pedestal termination PNP triode VT3 of earphone socket CZ; The fixed contact of earphone socket CZ meets the anodal VCC of connection circuit, and the moving contact of earphone socket CZ connects the positive pole of DC power supply DC.

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