CN202385067U

CN202385067U - Low frequency signal generating device

Info

Publication number: CN202385067U
Application number: CN2011204974777U
Authority: CN
Inventors: 李宁杭
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-04
Filing date: 2011-12-04
Publication date: 2012-08-15
Anticipated expiration: 2021-12-04

Abstract

The present utility model relates to a low frequency signal generating device. The low frequency signal generating device comprises a DC power supply DC, a common-emitter amplification circuit, a three-level RC phase shift circuit and an AC negative feedback circuit. The device is characterized in that the three-level RC phase shift circuit is connected in the common-emitter amplification circuit, and an emitting electrode of a PNP type transistor VT1 is connected with the AC negative feedback circuit. Through audio signal generators with professional purposes in the market has various functions and excellent performance, the price is high, and ordinary sound equipment professional personnel is difficult to accept. For making up and overcoming the above problem, an embodiment of the present utility model provides an audio signal generator made of an RC oscillator, the generator is used for measuring relevant technology data of a sound equipment circuit, and the low frequency signal generating device is concise in circuit structure, stable in working performance, good in use and low in costs.

Description

The low frequency signal generating means

Technical field

The utility model belongs to the application of electronic technology field, is about a kind of low frequency signal generating means.

Background technology

In design, debugging or maintenance process to acoustics circuit, the low frequency signal generating means is having important role aspect the technical indicator measurement of stereo set.In fact common low frequency generator is exactly an oscillating circuit, and the oscillating circuit kind mainly contains: a kind of LC of being oscillator; Another kind is the RC oscillator.The utility model is the low frequency generator made from the RC oscillator, is used for measuring the relevant technical data of acoustics circuit.

Though the audio signal generator function admirable of professional usefulness on the market, high, the general sound equipment professional of price is difficult to defectives such as acceptance.In order to overcome and to remedy these problems, develop that a kind of circuit structure is simple and direct, stable work in work, cheap, handy low frequency signal generating means be necessary.

Below specify the described low frequency signal generating means of the utility model related relevant technologies content in manufacturing process.

The utility model content

Goal of the invention and beneficial effect: though many, the function admirable of audio signal generator function of professional use on the market exists high, the general sound equipment professional of price to be difficult to defectives such as acceptance.In order to remedy and to overcome these problems; The low frequency signal generating means that the utility model embodiment makes with the RC oscillator; Be used for measuring acoustics circuit relevant technical indicator and related data, be that a kind of circuit structure is simple and direct, stable work in work, handy and cheap low frequency signal generating means.

The circuit working principle: the circuit of the described low frequency signal generating means of the utility model is with a RC phase shift oscillator; Signal phase difference in the circuit between the base stage of PNP transistor VT1 and the big utmost point of collection is 180 °; Constitute three grades of RC phase-shift circuits via resistance R 1～R3 and capacitor C 1～C3 again, the total phase difference of circuit is 360 °.Therefore, circuit is fed back to same-phase after through three grades of phase shifts, is positive feedback, has satisfied the phase condition of oscillating circuit and the requirement of oscillation amplitude.In order to increase the stability of RC phase shift oscillator circuit positive feedback work, in the common emitter amplifying circuit, be connected to the interchange negative-feedback circuit.

Technical scheme: low frequency signal generating means; By DC power supply DC, common emitter amplifying circuit, three grades of RC phase-shift circuits with exchange negative-feedback circuit and form; Its characteristic comprises: be connected to three grades of RC phase-shift circuits in the common emitter amplifying circuit, the emitter of PNP transistor VT1 is connected to the interchange negative-feedback circuit;

The common emitter amplifying circuit: the base stage of PNP transistor VT1 connects three grades of RC phase-shift circuits; The collector electrode of PNP transistor VT1 links to each other with an end of resistance R 5, the negative pole of electrochemical capacitor C5; The other end connection circuit negative pole VCC of resistance R 5; The positive pole of electrochemical capacitor C5 connects the low frequency signal lead-out terminal, and the emitter of PNP transistor VT1 connects the interchange negative-feedback circuit;

Three grades of RC phase-shift circuits: form by resistance R 1, resistance R 2, resistance R 3, resistance R 4, capacitor C 1, capacitor C 2 and capacitor C 3; The end of the base stage connecting resistance R3 of PNP transistor VT1, an end of resistance R 4 and an end of capacitor C 3; The other end connection circuit negative pole VCC of resistance R 4, the termination circuit ground GND of resistance R 3, the other end of capacitor C 3 links to each other with an end of capacitor C 2, an end of resistance R 2; The other end connection circuit ground GND of resistance R 2; The other end of capacitor C 2 links to each other with an end of capacitor C 1, an end of resistance R 1, the other end connection circuit ground GND of resistance R 1, the collector electrode of another termination PNP transistor VT1 of capacitor C 1;

Exchange negative-feedback circuit: form the end of the emitter connecting resistance R6 of PNP transistor VT1 and the negative pole of electrochemical capacitor C4, the anodal connection circuit ground GND of the other end of resistance R 6 and electrochemical capacitor C4 by resistance R 6, electrochemical capacitor C4.

Description of drawings

Accompanying drawing 1 is the embodiment circuit working schematic diagram that the utility model provides a low frequency signal generating means, and the VCC connection circuit negative pole in the accompanying drawing 1 connects the positive pole of DC power supply DC circuit.

Embodiment

Implement according to the circuit working schematic diagram of low frequency signal generating means shown in the accompanying drawing 1 and the components and parts specification requirement of description of drawings and the following stated, can realize the utility model.

The selection of components and parts and technical parameter thereof

VT1 is the positive-negative-positive silicon transistor, and model is 2SC9015, and β value >=80 also can be selected positive-negative-positive high frequency transistors such as penetrating current is little, the homemade model 3AG1C of working stability, 3AG1D for use;

Resistance is selected 1/8 metalfilmresistor for use, and the resistance of resistance R 1, R2 is 2K Ω, and the resistance of resistance R 3 is 8.2K Ω, and the resistance of resistance R 4 is 24K Ω, and the resistance of resistance R 5 is 1.1K Ω, and the resistance of resistance R 6 is 470 Ω;

C1～C3 is an oscillating capacitance, and selecting capacity for use is the terylene capacity of 0.047 μ F; C4 is for exchanging negative feedback electric capacity, and capacity is 30 μ F/16V; C5 is the audio frequency output coupling capacitor, and capacity is 50 μ F/16V;

DC is a DC power supply, and electric direct current is pressed and is 6V, uses No. 5 common alkaline batteries of 4 joints.

Circuit production and debugging

The circuit of low frequency signal generating means is so long as the electronic devices and components performance of selecting for use is intact; The annexation of components and parts is welded in the accompanying drawing to specifications; After physical connection line and welding quality process scrutiny were errorless, circuit need not debugged basically and get final product operate as normal.

The direct current retaining of serial connection universal instrument records the normal electrical flow valuve and is about 17mA in the collector loop of PNP transistor VT1.If it is bigger to record the operating current deviation, can suitably adjust the resistance of the biasing resistor R4 of PNP transistor VT1, make operating current reach normal value.

Technical indicator: on the low frequency signal lead-out terminal, connect the insert earphone of an impedance >=2000 Ω, connect the switch SW of the DC power supply DC of low frequency signal generating means, circuit can produce self-oscillation, can obtain the audio signal of 1kHz at audio signal output end.Under the condition of load impedance >=2000 Ω high resistants, the output voltage of low frequency signal is greater than 1000mV.

Claims

1. low frequency signal generating means comprises DC power supply DC, common emitter amplifying circuit, three grades of RC phase-shift circuits and exchanges negative-feedback circuit, and its characteristic comprises:

The base stage of PNP transistor VT1 in the common emitter amplifying circuit connects three grades of RC phase-shift circuits; The collector electrode of PNP transistor VT1 links to each other with an end of resistance R 5, the negative pole of electrochemical capacitor C5; The other end connection circuit negative pole VCC of resistance R 5; The positive pole of electrochemical capacitor C5 connects the low frequency signal lead-out terminal, and the emitter of PNP transistor VT1 connects the interchange negative-feedback circuit;

An end, an end of resistance R 4 and the end of capacitor C 3 of the base stage connecting resistance R3 of PNP transistor VT1 in three grades of RC phase-shift circuits; The other end connection circuit negative pole VCC of resistance R 4; The one termination circuit ground GND of resistance R 3; The other end of capacitor C 3 links to each other with an end of capacitor C 2, an end of resistance R 2, the other end connection circuit ground GND of resistance R 2, and the other end of capacitor C 2 links to each other with an end of capacitor C 1, an end of resistance R 1; The other end connection circuit ground GND of resistance R 1, the collector electrode of another termination PNP transistor VT1 of capacitor C 1.

2. low frequency signal generating means according to claim 1; It is characterized in that: the end of the emitter connecting resistance R6 of the PNP transistor VT1 in the interchange negative-feedback circuit and the negative pole of electrochemical capacitor C4, the anodal connection circuit ground GND of the other end of resistance R 6 and electrochemical capacitor C4.