CN219536036U

CN219536036U - OTL audio amplifier circuit

Info

Publication number: CN219536036U
Application number: CN202320701119.6U
Authority: CN
Inventors: 彭国兰; 丰海; 邓汉勇; 何连成
Original assignee: Xiamen City Vocational College Xiamen Open University
Current assignee: Xiamen City Vocational College Xiamen Open University
Priority date: 2023-04-03
Filing date: 2023-04-03
Publication date: 2023-08-15
Anticipated expiration: 2033-04-03

Abstract

The utility model provides an OTL audio amplifying circuit, which comprises an audio input source, an input stage, a pushing stage, an output stage bias circuit, a power output stage, a load and a power supply module; the audio input source is connected with the input of the input stage, the output of the input stage is connected with the input of the pushing stage, the output of the pushing stage is connected with the output stage bias circuit, the output stage bias circuit is connected with the input of the power output stage, the output of the power output stage is connected with the load, and the power module is used for providing power for the audio input source, the input stage, the pushing stage, the output stage bias circuit, the power output stage and the load; the audio input source comprises a miniature microphone, the load is a miniature loudspeaker, and audio amplification is realized through an input stage, a pushing stage, an output stage bias circuit and a power output stage; the utility model uses the OTL audio frequency amplifying circuit to complete the experiments of the voltage bias type single-tube amplifying circuit, the voltage amplifying circuit, the negative feedback circuit and the power amplifying circuit, and uses the audio frequency amplifying circuit to carry out the experiments, thereby increasing the interestingness.

Description

OTL audio amplifier circuit

Technical Field

The utility model relates to the field of experiments, in particular to an OTL audio amplifying circuit.

Background

At present, experiments of a voltage bias type single-tube amplifying circuit, a voltage amplifying circuit, a negative feedback amplifying circuit and a power amplifying circuit in a traditional analog electronic technology course are all completed by adopting an analog electronic technology experiment box, and the experiments of all circuits are completed sequentially. And the students finish wiring by contrasting the experimental circuit diagram, and gradually finish experimental contents and test circuit parameters according to experimental steps of the instruction book. The electronic components of the experiment box are welded, and students cannot touch the electronic components; in the experimental process, students only need to connect jumper wires, do not need to build circuits by themselves, and the picture reading capability and the board distribution capability of the students cannot be trained; in addition, the experimental effect of each circuit is not intuitively embodied, the experiment is boring and odorless, the learning interest of students cannot be stimulated, and the expected teaching effect cannot be achieved.

Disclosure of Invention

The main purpose of the utility model is to overcome the defects in the prior art, and provide an OTL audio amplifying circuit which comprises a signal input amplifying stage with higher input impedance, an output pushing stage and an OTL final output, and integrates a voltage bias type single-tube amplifying circuit, a voltage amplifying circuit, a negative feedback circuit and a power amplifying circuit; the miniature microphone is used as an audio input source, the miniature loudspeaker is used as a loudspeaker, the circuit function can be conveniently verified, and the experiment interestingness is strong.

The utility model adopts the following technical scheme:

an OTL audio amplifying circuit comprises an audio input source, an input stage, a pushing stage, an output stage biasing circuit, a power output stage, a load and a power module; the audio input source is connected with the input of the input stage, the output of the input stage is connected with the input of the pushing stage, the output of the pushing stage is connected with the output stage bias circuit, the output stage bias circuit is connected with the input of the power output stage, the output of the power output stage is connected with the load, and the power module is used for providing power for the audio input source, the input stage, the pushing stage, the output stage bias circuit, the power output stage and the load; the audio input source comprises a miniature microphone, the load is a miniature loudspeaker, and audio amplification is realized through an input stage, a pushing stage, an output stage bias circuit and a power output stage.

Specifically, the input stage includes: triode Q1, resistance R3, resistance R4, resistance R5, polarity electric capacity C2, polarity electric capacity C3 specifically is:

the base of triode Q1 passes through polarity electric capacity C1 to be connected miniature microphone's positive pole, the positive pole of polarity electric capacity C2 and the one end of resistance R3 are connected to triode Q1's projecting pole, resistance R4's one end is connected to resistance R4's the other end, resistance R4 and polarity electric capacity C3 are parallelly connected, and resistance R5's one end passes through resistance R16 and connects the power output stage, resistance R5's the other end is connected the power negative pole, resistance R3's the other end is connected the power positive pole, the promotion stage is connected to polarity electric capacity C2's negative pole.

Specifically, the push stage includes: triode Q2, resistance R8, resistance R13, electric capacity C7, resistance R7, polarity electric capacity C5 specifically is:

the base of triode Q2 connects the one end of resistance R13, the one end of resistance R8, the one end of resistance R13 and the one end of electric capacity C7, the other end of electric capacity C7 is connected to triode Q2's collecting electrode, the one end of resistance R7 is connected to triode Q2's projecting pole, the power negative pole is connected to resistance R7's the other end, polarity electric capacity C5 and resistance R7 are parallelly connected, the power negative pole is connected to resistance R8's the other end, the power output stage is connected to resistance R13's the other end, output stage biasing circuit is connected to triode Q2's collecting electrode.

Specifically, the output stage bias circuit includes: triode Q3, resistance R9, resistance R10, resistance R11, resistance R12 specifically is:

the resistor R11 is connected between the base electrode and the collector electrode of the triode Q3, the resistor R12 is connected between the base electrode and the emitter electrode of the triode Q3, the resistor R10 and the resistor R11 are connected between the collector electrode of the triode Q3 and the positive electrode of the power supply, and the collector electrode of the triode Q2 is connected with the emitter electrode of the triode Q3.

Specifically, the power output stage includes: triode Q4, triode Q5, triode Q6, triode Q7, resistance R14, resistance R15 specifically does:

the base of triode Q6 is connected to triode Q4's projecting pole, connecting resistance R14 and resistance R15 between triode Q4's projecting pole and triode Q5 projecting pole, triode Q7's base is connected to triode Q5 projecting pole, triode Q7's projecting pole is connected to triode Q6's projecting pole, the positive power supply is all connected to triode Q4's collecting electrode and triode Q6's collecting electrode, the negative power supply is all connected to triode Q5's collecting electrode and triode Q7's collecting electrode, triode Q3's collecting electrode is connected to triode Q4's base, triode Q5's base is connected to triode Q3's projecting pole, resistance R13's the other end is connected between resistance R14 and resistance R15, the load is connected through polarity electric capacity C4 to triode Q6's projecting pole.

As can be seen from the above description of the present utility model, compared with the prior art, the present utility model has the following advantages:

(1) The utility model provides an OTL audio amplifying circuit, which comprises an audio input source, an input stage, a pushing stage, an output stage bias circuit, a power output stage, a load and a power supply module; the audio input source is connected with the input of the input stage, the output of the input stage is connected with the input of the pushing stage, the output of the pushing stage is connected with the output stage bias circuit, the output stage bias circuit is connected with the input of the power output stage, the output of the power output stage is connected with the load, and the power module is used for providing power for the audio input source, the input stage, the pushing stage, the output stage bias circuit, the power output stage and the load; the audio input source comprises a miniature microphone, the load is a miniature loudspeaker, and audio amplification is realized through an input stage, a pushing stage, an output stage bias circuit and a power output stage; the utility model provides an OTL audio amplifying circuit, which is used for completing experiments on a voltage bias type single-tube amplifying circuit, a voltage amplifying circuit, a negative feedback circuit and a power amplifying circuit. The audio amplifying circuit is adopted for experiments, so that the interestingness is increased.

Drawings

Fig. 1 is a block diagram of an OTL audio amplifying circuit according to the present utility model.

Detailed Description

The utility model is further described below by means of specific embodiments.

Referring to fig. 1, a structure diagram of an OTL audio amplifying circuit provided by the present utility model is provided.

In addition, R17 provides power to the miniature microphone and acts as a load resistor for its internal active circuitry to function properly. The quiescent current of the miniature microphone is approximately 0.3mA to 0.4mA (the current flowing through R17). The power supply module is a 12V direct current power supply V1 and is connected with a capacitor C6 in parallel.

The triode Q1 is a core element of the input stage, and the R4 is used as an emitter static direct current feedback resistor for stabilizing a static working point. R5 is a current series negative feedback resistor of an alternating current signal in the input stage and is also a feedback network voltage dividing resistor of external series negative feedback (from the output final stage). The collector of transistor Q1, point D, is voltage stable.

The output load of the input stage comprises the input resistance of the pushing stage, and the input resistance of the pushing stage is lower (more than two hundred ohms) because of parallel negative feedback in the pushing stage, so that the gain of the input stage is seriously reduced, and the gain of the input stage is only 2-3 times.

The core element is a triode Q2. The output stage has feedback connected via R8 and R13 to the output stage, and the voltage of both AC and DC is negative feedback connected parallelly. The direct current negative feedback is used for stabilizing the voltage of the middle point (namely the point A) of the final output to be Vcc/2.

Although negative feedback of alternating current signals exists, the feedback depth is not large, and the input resistance of the parallel feedback is reduced, so that the voltage amplification factor of the parallel feedback can be more than 150 times and close to 200 times.

R11, R12 and Q3 form a static bias circuit of the output stage. As shown in fig. 1, the circuit between the point B and the point C acts as a regulator tube, and the voltage stabilizing value is ube×r12/(r11+r12). In this example, using 9013 pipe, the current between point B and point C was 2 mA-3 mA, then Ube≡0.62V.

Q4, Q6, and Q5, Q7 respectively form a composite transistor to increase current drive capability and together form an OTL. The load is a 8 ohm/0.5W micro horn.

The total gain provided by this embodiment, R16 and R5 form an outer loop deep negative feedback network, so

The experimental process comprises the following steps: first, an OTL audio amplifying circuit was simulated using multisim, and an output waveform was observed with an oscilloscope using a signal generator to generate a 50mV, 1kHz signal source. Students can deepen understanding and mastering the circuit through simulation experiments. And then, the students use the universal board to weld the OTL audio amplifying circuit, so as to realize the circuit function, analyze the circuit principle and write an experiment report.

The utility model provides an OTL audio amplifying circuit, which comprises an audio input source, an input stage, a pushing stage, an output stage bias circuit, a power output stage, a load and a power supply module; the audio input source is connected with the input of the input stage, the output of the input stage is connected with the input of the pushing stage, the output of the pushing stage is connected with the output stage bias circuit, the output stage bias circuit is connected with the input of the power output stage, the output of the power output stage is connected with the load, and the power module is used for providing power for the audio input source, the input stage, the pushing stage, the output stage bias circuit, the power output stage and the load; the audio input source comprises a miniature microphone, the load is a miniature loudspeaker, and audio amplification is realized through an input stage, a pushing stage, an output stage bias circuit and a power output stage; the utility model provides an OTL audio amplifying circuit, which is used for completing experiments on a voltage bias type single-tube amplifying circuit, a voltage amplifying circuit, a negative feedback circuit and a power amplifying circuit. The audio amplifying circuit is adopted for experiments, so that the interestingness is increased.

The foregoing is merely illustrative of specific embodiments of the present utility model, but the design concept of the present utility model is not limited thereto, and any insubstantial modification of the present utility model by using the design concept shall fall within the scope of the present utility model.

Claims

1. The OTL audio amplifying circuit is characterized by comprising an audio input source, an input stage, a pushing stage, an output stage bias circuit, a power output stage, a load and a power supply module; the audio input source is connected with the input of the input stage, the output of the input stage is connected with the input of the pushing stage, the output of the pushing stage is connected with the output stage bias circuit, the output stage bias circuit is connected with the input of the power output stage, the output of the power output stage is connected with the load, and the power module is used for providing power for the audio input source, the input stage, the pushing stage, the output stage bias circuit, the power output stage and the load; the audio input source comprises a miniature microphone, the load is a miniature loudspeaker, and audio amplification is realized through an input stage, a pushing stage, an output stage bias circuit and a power output stage.

2. The OTL audio amplification circuit of claim 1, wherein the input stage comprises: triode Q1, resistance R3, resistance R4, resistance R5, polarity electric capacity C2, polarity electric capacity C3 specifically is:

3. The OTL audio amplification circuit of claim 1, wherein the boost stage comprises: triode Q2, resistance R8, resistance R13, electric capacity C7, resistance R7, polarity electric capacity C5 specifically is:

the base electrode of the triode Q2 is connected with one end of a resistor R13, one end of a resistor R8, one end of the resistor R13 and one end of a capacitor C7; the other end of electric capacity C7 is connected to triode Q2's collecting electrode, and triode Q2's projecting pole one end of connecting resistance R7, and power negative pole is connected to resistance R7's the other end, and polarity electric capacity C5 and resistance R7 are parallelly connected, and power negative pole is connected to resistance R8's the other end, and power output stage is connected to resistance R13's the other end, and output stage bias circuit is connected to triode Q2's collecting electrode.

4. The OTL audio amplification circuit of claim 1, wherein the output stage bias circuit comprises: triode Q3, resistance R9, resistance R10, resistance R11, resistance R12 specifically is:

5. The OTL audio amplification circuit of claim 1, wherein the power output stage comprises: triode Q4, triode Q5, triode Q6, triode Q7, resistance R14, resistance R15 specifically does: