CN101957599A - Single-stage amplifying circuit with automatically adjustable quiescent point - Google Patents

Abstract

The invention discloses a single-stage amplifying circuit with automatically adjustable quiescent point, which belongs to the application field of the electronic technology. The single-stage amplifying circuit comprises a singlechip, a digital potentiometer, the single-stage amplifying circuit, an A/D converting circuit, and a keyboard circuit and a display circuit which are connected with the singlechip. The single-stage amplifying circuit is characterized in that: resistors R1, R2, R4 and R5 are adjustable resistors in the digital potentiometer; the singlechip can control resistance values of resistors R1, R2, R4 and R5; the A/D converting circuit is used for monitoring the value of the static work point; and the keyboard circuit and the display circuit are used for setting and displaying the value of the static work point respectively. The single-stage amplifying circuit of the invention has the advantages that: the plurality of adjustable resistors inside the digital potentiometer replace an ordinary potentiometer adjusted manually, so that the resistance value of the digital potentiometer is controlled by the singlechip so as to adjust the static work point of the single-stage amplifying circuit in real time.

Description

The self-adjustable single-stage amplifying circuit of a kind of quiescent point

Technical field

The present invention is the self-adjustable single-stage amplifying circuit of a kind of quiescent point, belongs to the application of electronic technology field, can be used in Experiment of Electronic Technology equipment, various instrument and meter and the control module.

Background technology

Present some university's electricity type student Experiment of Electronic Technology exercise equipments and single chip computer experiment exercise equipment are separate, the experiment training resource does not organically combine, the experimental resources utilization factor is low, it is a kind of wasting of resources, the knowledge of student's study effectively, continuously, does not synthetically obtain consolidating and using yet, and the single-stage amplifying circuit is a content in university's electricity type student " electronic technology " curriculum experiment training; In the control module of some instrument and meters, the quiescent point of determining the single-stage amplifying circuit all adopts the mode of manual adjustments potentiometer, real-time regulated poor ability.

Summary of the invention

Mutually combining between the experiment training that the objective of the invention is to solve single-stage amplifying circuit in " electronic technology " curriculum experiment is trained with the single-chip microcomputer actual program, solve the problem that disconnects mutually between two kinds of experimental facilitiess, solve continuity, steadiness, comprehensive, the amalgamation problem of knowledge learning; Solve the problem of the quiescent point real-time regulated poor ability of single-stage amplifying circuit in the practical application.

To achieve these goals, the present invention has taked following technical scheme:

The self-adjustable single-stage amplifying circuit of a kind of quiescent point comprises single-chip microcomputer, digital regulation resistance, single-stage amplifying circuit, A/D change-over circuit and keyboard circuit that is connected with single-chip microcomputer and display circuit; The resistance value of adjustable resistor R1, R2, R4, R5 in the output regulating and controlling digital regulation resistance of single-chip microcomputer, the output of digital regulation resistance inserts the single-stage amplifying circuit; The magnitude of voltage of A/D change-over circuit monitoring single-stage static work point of enlarged circuits also feeds back to single-chip microcomputer; Keyboard circuit and display circuit are as the setting and the demonstration of the value of quiescent point.

In the self-adjustable single-stage amplifying circuit of above-mentioned a kind of quiescent point, it is 89C52 that described single-chip microcomputer adopts the chip model, it is X9241U that described digital regulation resistance adopts the chip model, and described single-stage amplifying circuit is formed specifically being connected between each device by NPN type triode T:

1,2 pin of 89C52 connect 14,9 pin of X9241U respectively, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4,5,15,16,10 pin of X9241U link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3,1 pin of X9241U link together and with+U _CCPower supply connects, resistance R ₃An end connection+U _CCPower supply, resistance R ₃The other end connect the collector of triode T, 2,6,8 pin of X9241U link together and are connected with the base stage of triode T, 11,13,17,19 pin of X9241U link together and are connected with the emitter of T, 7,12,18 pin of X9241U link together and are connected capacitor C with the ground of+5V power supply ₁An end connect input signal u _i, capacitor C ₁The other end connect the base stage of triode T, capacitor C ₂An end connect output signal u _o, capacitor C ₂The other end connect the collector of triode T, capacitor C ₃An end connect the emitter of triode T, capacitor C ₃Other end connection+U _CCThe ground of power supply ,+5V power supply and+U _CCPower supply altogether.

The invention has the advantages that the common manual regulator potentiometer that replaces being used to change the single-stage static work point of enlarged circuits with a plurality of adjustable resistors in the digital regulation resistance, thereby, realize the quiescent point of real time altering single-stage amplifying circuit by resistance value with the Single-chip Controlling digital regulation resistance.

Description of drawings:

The self-adjustable single-stage amplifying circuit of Fig. 1 quiescent point block diagram

The self-adjustable single-stage amplification circuit diagram of Fig. 2 quiescent point

Embodiment:

The present invention is described in detail below in conjunction with accompanying drawing 1, Fig. 2.

The self-adjustable single-stage amplifying circuit of quiescent point block diagram as shown in Figure 1, the self-adjustable single-stage amplification circuit diagram of quiescent point is as shown in Figure 2.In Fig. 1, single-chip microcomputer links together by the mode and the digital regulation resistance of serial communication, a plurality of adjustable resistors of digital regulation resistance are connected with the single-stage amplifying circuit, the quiescent point of single-stage amplifying circuit is determined by a plurality of adjustable resistors, keyboard circuit connects single-chip microcomputer and can be used for keying in corresponding static work point value or out of Memory, display circuit connects quiescent operation point value or the out of Memory that single-chip microcomputer is used for display setting, and the A/D change-over circuit is used for monitoring the quiescent operation point value of single-stage amplifying circuit.

Fig. 2 is concrete connecting circuit figure.In Fig. 2,89C52 is a single-chip microcomputer; X9241U is a digital regulation resistance, include 4 adjustable resistors, 1,2,3 pin wherein, 6,7,8 pin, 11,12,13 pin, 17,18,19 pin are respectively three pins of 4 adjustable resistors in the digital regulation resistance, with these 4 adjustable resistors difference called after resistance R ₁, R ₂, R ₄, R ₅, wherein 1 pin, 6 pin, 13 pin, 19 pin are the scalable end of 4 resistance, resistance R ₄, R ₅It is relation in parallel; T is a NPN type triode, and physical circuit connects as follows:

1,2 pin of 89C52 connect 14,9 pin of X9241U respectively, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4,5,15,16,10 pin of X9241U link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3,1 pin of X9241U link together and with+U _CCPower supply connects, resistance R ₃An end connection+U _CCPower supply, resistance R ₃The other end connect the collector of triode T, 2,6,8 pin of X9241U link together and are connected with the base stage of triode T, 11,13,17,19 pin of X9241U link together and are connected with the emitter of T, 7,12,18 pin of X9241U link together and are connected capacitor C with the ground of+5V power supply ₁An end connect input signal u _i, capacitor C ₁The other end connect the base stage of triode T, capacitor C ₂An end connect output signal u _o, capacitor C ₂The other end connect the collector of triode T, capacitor C ₃An end connect the emitter of triode T, capacitor C ₃Other end connection+U _CCThe ground of power supply ,+5V power supply and+U _CCPower supply altogether.A/D change-over circuit, keyboard circuit and display circuit and single-chip microcomputer be connected to general custom circuit connection, do not provide physical circuit.

Concrete working method is as follows:

As shown in Figure 2,1,89C52 passes through, and 2 pin are connected with 14,9 pin of X9241U, set up serial communication each other, single-chip microcomputer is with this resistance value that changes the inner a plurality of potentiometers of digital regulation resistance, and concrete communication mode each other can be consulted the operation instruction of X9241U; The single-stage static work point of enlarged circuits generally is made up of 4 values: the electric current I that flows through triode T collector _C, flow through the electric current I of triode T base stage _B, the voltage U between triode T base stage and the emitter _BE, the voltage U between triode T collector and the emitter _CEThese 4 values can be by regulating resistance R ₁, R ₂, R ₄, R ₅Determine; The concrete computing formula of these 4 values is:

$V_B\≈\frac{R_2}{R_1+R_2}{U}_{\mathrm{CC}}...\left(1\right)$

$I_C\≈I_E=\frac{V_B-U_{\mathrm{BE}}}{R_4//R_5}...\left(2\right)$

$I_B\≈\frac{I_C}{\mathrm{\β}}...\left(3\right)$

U _CE≈U _CC-(R ₃+R ₄//R ₅)I _C …………··(4)

(2) I in the formula _EFor flowing through the electric current of triode T emitter, U _BEValue can generally get U according to the decision of the model of triode _BE=0.7V, the β in (3) formula is the current amplification factor of triode, can measure by specialized equipment.

Claims (2)

1. the self-adjustable single-stage amplifying circuit of quiescent point belongs to the application of electronic technology field.Comprise single-chip microcomputer, digital regulation resistance, single-stage amplifying circuit, A/D change-over circuit and keyboard circuit that is connected with single-chip microcomputer and display circuit; It is characterized in that: adjustable resistor R in the output regulating and controlling digital regulation resistance of single-chip microcomputer ₁, R ₂, R ₄, R ₅Resistance value, the output of digital regulation resistance inserts the single-stage amplifying circuit; The magnitude of voltage of A/D change-over circuit monitoring single-stage static work point of enlarged circuits also feeds back to single-chip microcomputer; Keyboard circuit and display circuit are as the setting and the demonstration of the value of quiescent point.

2. the self-adjustable single-stage amplifying circuit of a kind of quiescent point according to claim 1, it is characterized in that: it is 89C52 that described single-chip microcomputer adopts the chip model, it is X9241U that described digital regulation resistance adopts the chip model, described single-stage amplifying circuit is formed specifically being connected between each device by NPN type triode T:

1,2 pin of 89C52 connect 14,9 pin of X9241U respectively, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4,5,15,16,10 pin of X9241U link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3,1 pin of X9241U link together and with+U _CCPower supply connects, resistance R ₃An end connection+U _CCPower supply, resistance R ₃The other end connect the collector of triode T, 2,6,8 pin of X9241U link together and are connected with the base stage of triode T, 11,13,17,19 pin of X9241U link together and are connected with the emitter of T, 7,12,18 pin of X9241U link together and are connected capacitor C with the ground of+5V power supply ₁An end connect input signal u _i, capacitor C ₁The other end connect the base stage of triode T, capacitor C ₂An end connect output signal u _o, capacitor C ₂The other end connect the collector of triode T, capacitor C ₃An end connect the emitter of triode T, capacitor C ₃Other end connection+U _CCThe ground of power supply ,+5V power supply and+U _CCPower supply altogether.

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