CN206907307U - Analogous circuit experiment device for teaching - Google Patents

Abstract

The utility model discloses an analog circuit experiment device for teaching, which comprises a power circuit and an analog circuit teaching module; Circuit devices are connected or disconnected, and signal sampling points are set at key signal points in the analog circuit signal transmission loop to lead out circuit signals. The utility model uses a jumper to change the circuit function; during the experimental operation, it is only necessary to perform simple plugging and unplugging of the jumper cap according to the experimental content. Pay attention to the experimental principle and experimental measurement, eliminate the phenomenon of power supply or component burnout caused by dangerous wiring, and save a lot of time for troubleshooting wiring errors. The utility model has the advantages of free wiring, high reliability of the circuit experiment device, long service life and convenient later maintenance.

Description

Analog circuit experiment device for teaching

technical field

The utility model specifically relates to an analog circuit experiment device for teaching.

Background technique

At present, with the development of my country's economy and technology and the improvement of education level, countless high school graduates have entered the university campus and started a new learning journey.

In university education, the study of analog circuits is an important part of university science and engineering education. Among them, the learning of analog circuits is best in the form of circuit experiments. Therefore, courses for learning analog circuit experiments have been popularized in colleges and vocational colleges across the country.

However, because students lack experience in circuit construction when learning analog circuits, and in order to ensure the safety of experiments, colleges and vocational colleges in my country now use fixed analog circuit experimental devices (such as analog circuit test boxes ) to learn. The analog circuit test box directly solidifies the analog circuit in the test box, and exercises students' hands-on ability by setting certain wiring holes, so that students can experience the process of circuit construction, and speed up students' understanding and learning in the process of circuit construction .

However, the traditional analog circuit experiment box adopts the design scheme of separating components and connecting them with stacked wires, which can easily lead to many problems, for example: 1. There is no connection between devices on some experiment boxes, and each component is isolated. Integrity, and there is no schematic diagram reflected on the panel of the experiment box, which is not suitable for guiding students to learn the principle of circuits; 2. Due to long-term use, the stacked jacks on the panel of the experiment box are prone to loosening, resulting in poor contact. This problem It is difficult to detect, and maintenance is time-consuming and laborious, wasting limited classroom time. 3. Due to long-term unplugging and pulling, the inner metal wire of the patch cord is broken, but the outer insulation layer is not damaged at all. This problem is difficult for students to find. Once the splice wire breaks, it must be replaced with a new one. Each experimental box is equipped with dozens of stacking cables, which is a long-standing and difficult problem in management. 4. The use and unplugging of a large number of stacked wires may easily lead to wiring errors and burn the power supply or circuit components. At the same time, it takes a lot of time to check, which may eventually cause students to be unable to complete the experiment within the limited classroom time.

Utility model content

The purpose of the utility model is to provide an analog circuit experiment device for teaching which is free of wiring, has high reliability, long service life and convenient maintenance in the later stage.

The analog circuit experimental device for teaching provided by the utility model includes a power circuit and an analog circuit teaching module; the power circuit supplies power; Connect or disconnect analog circuit devices, and set signal sampling points at key signal points of the analog circuit signal transmission loop, to quickly extract key analog circuit signals for sampling or to an oscilloscope for observation.

The setting of the signal sampling point at the key signal point of the analog circuit signal transmission loop is specifically to use a triangle test loop to lead out the signal at the key signal point of the analog circuit signal transmission loop.

The analog circuit teaching module includes signal source circuit, rectification-filtering-integrated voltage stabilization experimental circuit, square wave generation experimental circuit, RC sine wave oscillation experimental circuit, integrated power amplification experimental circuit, integrated operational amplifier experimental circuit, complementary symmetrical power Amplification experiment circuit, FET amplification experiment circuit, differential amplification experiment circuit and triode unipolar-two-stage-negative feedback amplification experiment circuit.

The power supply circuit includes a positive and negative 12V power supply circuit, a +5V power supply circuit and a +15V power supply circuit, and a jumper cap and a signal sampling point are connected to the +12V power supply output end and the -12V power supply output end of the positive and negative 12V power supply circuit , used to manually control the polarity of the output power supply, and at the same time, a signal sampling point is also set at the common ground of the +12V power supply output terminal and the -12V power supply output terminal; the signal sampling point is used to lead out the corresponding circuit signal.

The rectification-filtering-integrated voltage stabilization experimental circuit includes a step-down transformer with a common ground terminal on the secondary side, a rectifier bridge, a filter circuit, a voltage stabilizing chip, an output filter and a load; the common ground terminal of the secondary side of the step-down transformer is grounded The output of the secondary side of the transformer is rectified by the rectifier bridge to obtain positive and negative power supply signals, and then filtered by the respective filter circuits to obtain two stable DC current signals input to the two voltage regulator chips, and the output terminals of the two voltage regulator chips Output a positive power supply and a negative power supply respectively, and output a stable voltage signal after being filtered by an output filter; wherein, a first jumper cap is also set on the output positive bridge arm of the rectifier bridge, and a The second jumper cap leads to the first signal sampling point, and a third jumper cap is connected in series between the output end of the filter circuit and the input end of the voltage regulator chip and leads to the second signal sampling point. A fourth jumper cap is connected in series after the filter circuit at the output negative end of the negative terminal and leads to the third signal sampling point. The output terminals of the two voltage regulator chips respectively lead to the fourth signal sampling point and the fifth signal sampling point; the load includes the first A load resistor, a second load resistor and a sliding rheostat, the output terminal of the first voltage regulator chip is connected to the second circuit through the fifth jumper cap, the first load resistor, the sliding rheostat, the second load resistor and the sixth jumper cap The output end of the voltage regulator chip and the sliding end of the sliding rheostat are grounded, and the sixth signal sampling point is also drawn out at the same time.

The described integrated power amplification experimental circuit includes an integrated power amplifier model LM386; the 3 pins of the integrated power amplifier lead to the first signal sampling point, the 2 pins and 4 pins are grounded, and the 1 pin is connected to the first jumper cap through a bootstrap capacitor 8 pins, 7 pins are grounded through the filter capacitor, 6 pins are connected to the positive pole of the power supply, and also grounded through the power filter capacitor, and also grounded through the current limiting resistor and the LED indicator light, and 5 pins are output pins, which lead to the second The signal sampling point is also grounded through the RC circuit, and also grounded through the second jumper cap and the speaker; the ground signal also leads to the third signal sampling point.

The described integrated operational amplifier experimental circuit includes a model of an operational amplifier chip of LM741; 4 pins of the chip are connected to the negative pole of the power supply, 7 pins are connected to the positive pole of the power supply, and 6 pins are the output terminal, which directly leads to the sixth signal sampling point; the first jumper cap One end of the jumper cap is connected to the output end of the chip, the other end is connected to pin 2 of the chip, and at the same time, the first signal collection point is drawn out through a broken wire; one end of the second jumper cap is connected to the output end of the chip through the second capacitor, and the other end is connected to pin 2 of the chip At the same time, the second signal sampling point is also drawn out through the first capacitor; one end of the third jumper cap is connected to the output end of the chip through the first resistor, and the other end is connected to pin 2 of the chip, and the third signal sampling point is drawn out through the second resistor ; One end of the fourth jumper cap is connected to the output terminal of the chip through the third resistor, and the other end is connected to the 2 pin of the chip, and the fourth signal sampling point is also drawn out through the fourth resistor; the 3 pin of the chip is the input positive pin, through The fifth resistor leads to the fifth signal sampling point, and at the same time is grounded through the sixth resistor; the ground signal directly leads to the ground signal sampling point.

In the complementary symmetrical power amplification experiment circuit, the first signal sampling point is divided into three paths after passing through the first capacitor, one path is grounded through the second resistor, the second path is connected to the base of the first triode, and the third path is passed through The first resistor and the sliding rheostat are connected to one end of the first jumper cap; the other end of the first jumper cap is connected in series with the second capacitor, and the fifth resistor is connected to the positive pole of the power supply; one end of the fourth resistor is connected to the second capacitor connected in series. Between the capacitor and the fifth resistor, the other end is connected to the collector of the first transistor through a diode, and also connected to the base of the third transistor; the emitter of the first transistor is grounded through the third resistor; The two ends of the two jumper caps are connected in parallel to the two ends of the diode; the base of the second triode is connected between the fourth resistor connected in series and the diode, the collector of the second triode is connected to the positive pole of the power supply, and the emitter Then connect to the movable end of the sliding rheostat through the sixth resistor, and at the same time continue to connect to the emitter of the third triode through the seventh resistor; the movable end of the sliding rheostat is connected in series with the third capacitor to lead to the second signal sampling point, and at the same time The third jumper cap and the load resistor are also connected in series and then grounded; a light-emitting diode and a current limiting resistor are directly connected between the positive pole of the power supply and the ground; the ground signal is directly led to the ground signal sampling point; the first triode and the second triode are both An NPN transistor is used, and the third transistor adopts a PNP transistor.

In the field effect tube amplification experiment circuit, the first signal sampling point is connected in series with the first input resistor, the first jumper cap and the second input resistor and then grounded; one end of the second jumper cap is connected to the serially connected first input resistor and the first jumper cap, the other end directly leads to the second signal sampling point, and at the same time, the first capacitor is connected in series to the gate of the field effect transistor, and the fifth resistor and the first motor are also grounded; the fourth jumper One end of the cap is connected between the fifth resistor and the first resistor, and the other end is connected in series with the sliding rheostat and the third jumper cap and then connected to the positive pole of the power supply; the source of the field effect tube is grounded through the fourth resistor; the drain of the field effect tube Connect the positive pole of the power supply through the sliding rheostat and the third resistor, and at the same time connect the second capacitor in series to lead to the second signal sampling point; the second signal sampling point is also connected to the ground through the fifth jumper cap and the third capacitor connected in series. The second signal is grounded through the sixth signal sampling point connected in series and the load resistor; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground; the ground directly leads to the ground signal sampling point; the field effect transistor adopts an N-channel insulated gate field effect tube.

In the differential amplification experimental circuit, one end of the third resistor and one end of the sixth resistor are both connected to the positive pole of the power supply, and the other end of the third resistor directly leads to the first signal sampling circuit and is connected to the collector of the first triode at the same time. The base of the first transistor is grounded through the second resistor and the first resistor, and the first signal sampling point is drawn between the second resistor and the first resistor; the base of the second transistor passes through the seventh resistor and the tenth resistor The resistor is grounded, and the second signal sampling point is drawn between the seventh resistor and the tenth resistor; the emitters of the first triode and the second triode are connected together through a sliding rheostat; the movable end of the sliding rheostat is connected to the first Jumper cap and one end of the second jumper cap, the other end of the first jumper cap is connected to the negative power supply through the fourth resistor; the other end of the second jumper cap is connected to the collector of the third triode, and the third triode The emitter of the tube is connected to the negative power supply through the fifth resistor, the base of the third triode is connected to the negative power supply through the ninth resistor, and is also grounded through the eighth resistor; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground ; The ground directly leads to the ground signal sampling point; the first, second and third triodes all use NPN type triodes.

In the triode unipolar-two-stage-negative feedback amplification experimental circuit, the first signal sampling point is grounded through the first input resistor, the first jumper cap and the second input resistor; Connect one end of the second jumper cap, the other end of the second jumper cap directly leads to the second signal sampling point, and connect the first capacitor in series to form three signals: the first signal passes through the sliding rheostat and the first resistor Connect the positive pole of the power supply, the second signal is grounded through the third jumper cap and the second resistor, the third signal is directly connected to the base of the first triode; the emitter of the first triode passes through the fourth resistor and the fifth The resistor is grounded; one end of the fifth jumper cap is also connected between the fourth resistor and the fifth resistor, and the other end of the fifth jumper cap is grounded through the fourth capacitor; the collector of the first triode is connected through the third resistor The positive pole of the power supply; the fourth jumper cap is connected to both ends of the third resistor; the collector of the first triode also passes through the second capacitor to form three signals: the first signal directly leads to the third signal sampling point, and the second The second signal is grounded through the seventh jumper cap and the first load resistor, and the third signal is connected to the base of the second triode after passing through the eighth jumper cap; the base of the second triode is also passed through the second slide The rheostat and the tenth resistor are connected to the positive pole of the power supply, and are also grounded through the sixth resistor; the emitter of the second triode is grounded through the eighth resistor and the ninth resistor; the ninth jumper is also connected between the eighth resistor and the ninth resistor One end of the cap, the other end of the ninth jumper cap is grounded through the sixth capacitor; the collector of the second triode is connected to the positive pole of the power supply through the seventh resistor, and the third signal sampling point is also drawn out through the fifth capacitor; the third signal The sampling point is also grounded through the tenth jumper cap and the second load resistor, and the third signal sampling point is also connected to the emitter of the first triode through the feedback resistor connected in series, the sixth jumper cap, and the third capacitor; A light-emitting diode and an idler resistor are connected between the anode and the ground; the ground directly leads to a ground signal sampling point; the first and second transistors are all NPN transistors.

The analog circuit experiment device for teaching provided by the utility model uses a jumper to change the circuit function; during the experimental operation, only a simple jumper cap needs to be removed and inserted according to the experimental content, and there is no need to use a stacked wire for plugging and unplugging operations , you don’t need to worry about various problems caused by wrong wiring, you only need to pay attention to the experimental principle and experimental measurement, which eliminates the phenomenon of power supply or component burnout caused by dangerous wiring, and saves a lot of time for troubleshooting wrong wiring; in addition, the input and output of all modules , grounding, and other possible test points are drawn out with triangular test rings, which are eye-catching and easy to hold with alligator clips or oscilloscope probes. Such a design can standardize the measurement operation of students, avoid damage to expensive test instruments caused by students' misuse, and also reduce the loss of signal generator lead-out connectors and oscilloscope probes to a certain extent. The utility model has the advantages of free wiring, high reliability of the circuit experiment device, long service life and convenient later maintenance.

Description of drawings

Fig. 1 is the circuit principle diagram of the positive and negative 12V power supply circuit of the power supply circuit of the present invention.

Fig. 2 is the schematic circuit diagram of the +5V and +15V power supply circuits of the power supply circuit of the present invention.

FIG. 3 is a schematic circuit diagram of the signal source circuit of the present invention.

Fig. 4 is a schematic circuit diagram of the rectification-filtering-integrated voltage stabilizing experimental circuit of the present invention.

Fig. 5 is the circuit schematic diagram of the square wave generating circuit of the present invention.

FIG. 6 is a schematic circuit diagram of the RC sine wave oscillation circuit of the present invention.

Fig. 7 is a schematic circuit diagram of the integrated power amplifier test circuit of the present invention.

Fig. 8 is a schematic circuit diagram of the integrated operational amplifier test circuit of the present invention.

FIG. 9 is a schematic circuit diagram of a complementary symmetrical power amplification experimental circuit of the present invention.

Fig. 10 is a schematic circuit diagram of the FET amplification experiment circuit of the present invention.

Fig. 11 is a schematic circuit diagram of a differential amplification experiment circuit of the present invention.

Fig. 12 is a schematic circuit diagram of a triode unipolar-two-stage-negative feedback amplification experimental circuit of the present invention.

detailed description

As shown in Figure 1, it is the circuit principle diagram of the positive and negative 12V power supply circuit of the power supply circuit of the present invention: the common ground terminal of the secondary side of the step-down transformer T1 is grounded; the output of the secondary side of the transformer is rectified by the rectifier bridge (D1~D4) The positive and negative power supply signals are filtered by their respective filter circuits (capacitors C1~C4) to obtain two stable DC current signals input to two voltage regulator chips (chip U1-LM7812 and chip U2-LM7912), two The output terminals of the voltage regulator chip output a positive power supply and a negative power supply respectively, and output a stable voltage signal after filtering through the output filter (C5 and C6); at the +12V power supply output terminal and -12V power supply output terminal of the positive and negative 12V power supply circuit A jumper cap and a signal sampling point are connected to manually control the polarity of the output power supply. At the same time, a signal sampling point is also set at the common ground of the +12V power supply output terminal and the -12V power supply output terminal; the signal sampling point is used for Lead to the corresponding circuit signal. When using, if you need to use +12V power supply, connect the first jumper cap; if you need to use -12V power supply, connect the second jumper cap.

As shown in Figure 2, it is the circuit schematic diagram of the +5V and +15V power supply circuit of the power supply circuit of the present utility model: the secondary output of the transformer T1 is rectified by the rectifier bridge (D1~D4) to obtain a positive power supply signal, and filtered by the capacitor C1 , one way is input to the input terminal of the power chip U1 (model LM2575-5.0), and the chip outputs +5V power signal; the other power signal is input to the input terminal of the power chip U2 (model LM2575), and the output terminal of the chip outputs +15V power. At the same time, the feedback pin 4 of the chip samples the output signal through the sliding rheostat RW1, so that the output voltage of the chip can be adjusted.

As shown in Figure 3, it is the circuit schematic diagram of the signal source circuit of the present utility model: the signal source circuit mainly adopts the chip of model ICL8038 to form; 6 pins and 8 pins of the chip are connected to the positive pole of the power supply, and 10 pins of the chip are connected to the frequency adjustment circuit; Pin 11 of the chip is connected to the negative power supply, pin 12 is connected to the movable end of the sliding rheostat, and the sliding rheostat is connected between the positive pole of the power supply and the negative power supply; pin 1 and pin 12 of the chip are connected to the same circuit; pin 2 and pin 3 of the chip are connected to the waveform Selection circuit; pin 4 and pin 5 of the chip are connected to the square wave duty cycle adjustment circuit; the output terminal of the chip circuit is connected to the amplifier circuit composed of two operational amplifiers through the resistor R8, so that the amplitude of the output signal of the signal generating circuit can be adjusted Tune.

As shown in Figure 4 is the circuit schematic diagram of the rectification-filtering-integrated voltage stabilizing experimental circuit of the present invention: the common ground terminal of the secondary side of the step-down transformer is grounded; the output of the secondary side of the transformer is rectified by the rectifier bridge to obtain positive and negative power supplies The signals are filtered by their respective filter circuits, so that two stable DC current signals are input into two voltage regulator chips, and the output terminals of the two voltage regulator chips output one positive power supply and one negative power supply respectively, which are filtered by the output filter Output a stable voltage signal; wherein, a first jumper cap is also provided on the output positive bridge arm of the rectifier bridge, and a second jumper cap is connected in series at the output end of the rectifier bridge and leads to the first signal sampling point. A third jumper cap is connected in series between the output end of the circuit and the input end of the voltage regulator chip, leading to the second signal sampling point, and a fourth jumper cap is connected in series behind the filter circuit at the output negative end of the rectifier bridge And lead to the third signal sampling point, the output terminals of the two voltage regulator chips lead to the fourth signal sampling point and the fifth signal sampling point respectively; The output end of the pressing chip is connected to the output end of the second voltage stabilizing chip through the fifth jumper cap, the first load resistor, the sliding rheostat, the second load resistor and the sixth jumper cap, and the sliding end of the sliding rheostat is grounded. Lead out the sixth signal sampling point. In specific use, during normal experiments, connect the first and second jumper caps; when only performing rectification-filtering experiments, connect the first and second jumper caps, and disconnect the third and fourth jumper caps; When the integrated voltage regulator module is tested, connect the first to fourth jumper caps; when the load needs to be connected, connect the first to sixth jumper caps at the same time.

As shown in Figure 5, it is the circuit schematic diagram of the square wave generating circuit of the present utility model: the square wave generating circuit adopts a mature square wave generating circuit composed of operational amplifier LM741 and some resistors and capacitors.

As shown in Figure 6, it is the circuit principle diagram of the RC sine wave oscillation circuit of the present utility model: similarly, the RC sine wave oscillation circuit adopts a mature RC sine wave oscillation circuit composed of operational amplifier LM741 and some resistors and capacitors.

As shown in Figure 7, it is the circuit schematic diagram of the integrated power amplifier test circuit of the present invention: the 3 pins of the integrated power amplifier lead out the first signal sampling point, the 2 pins and 4 pins are grounded, and the 1 pin passes through the bootstrap capacitor and the first jump The wire cap is connected to pin 8, pin 7 is grounded through the filter capacitor, pin 6 is connected to the positive pole of the power supply, and grounded through the filter capacitor of the power supply, and grounded through the current limiting resistor and the LED indicator light at the same time, pin 5 is the output pin, after passing through the filter capacitor The second signal sampling point is drawn out, and at the same time grounded through the RC circuit, and also grounded through the second jumper cap and the speaker; the ground signal also leads out to the third signal sampling point. During the experiment, if it is necessary to increase the voltage gain of the signal, connect the first jumper cap and access the bootstrap capacitor C1.

As shown in Figure 8, it is the circuit schematic diagram of the integrated operational amplifier experimental circuit of the present utility model: the integrated operational amplifier experimental circuit includes an operational amplifier chip whose model is LM741; the 4 pins of the chip are connected to the negative pole of the power supply, the 7 pins are connected to the positive pole of the power supply, and the 6 pins are connected to the positive pole of the power supply. It is the output terminal, which leads directly to the sixth signal sampling point; one end of the first jumper cap is connected to the chip output end, the other end is connected to the 2 pin of the chip, and at the same time leads to the first signal collection point through a broken wire; one end of the second jumper cap Connect the output end of the chip through the second capacitor, and connect the other end to pin 2 of the chip, and at the same time lead out the second signal sampling point through the first capacitor; one end of the third jumper cap is connected to the output end of the chip through the first resistor, and the other end Connect pin 2 of the chip, and at the same time lead out the third signal sampling point through the second resistor; one end of the fourth jumper cap is connected to the output end of the chip through the third resistor, and the other end is connected to pin 2 of the chip, and at the same time lead out through the fourth resistor The fourth signal sampling point; pin 3 of the chip is the input positive pin, which leads to the fifth signal sampling point through the fifth resistor, and is also grounded through the sixth resistor; the ground signal directly leads to the ground signal sampling point. In the specific experiment, connect the third jumper cap and input the signal from Vi1 when connecting the inverse proportional amplification circuit; connect the fourth jumper cap and input the signal from Vi+ when connecting the same phase proportional amplification circuit; connect the inverting addition circuit, Then connect the third jumper cap, the signal is input from Vi1 and Vi2; connect the subtraction circuit, then connect the third jumper cap, the signal is input from Vi+ and Vi2; connect the integration circuit, then connect the second jumper cap, the signal is from Vi1 and Vi2 Vi2 input; connect the differential circuit, then connect the third jumper cap, the signal is input from Vi3; connect the voltage follower circuit, then connect the first jumper cap, the signal is input from Vi+.

As shown in Figure 9, it is the circuit schematic diagram of the complementary symmetrical power amplification experiment circuit of the present invention: the first signal sampling point passes through the first capacitor and the signal is divided into three paths, one path is grounded through the second resistor, and the second path is connected to the first three paths. The base of the pole tube, the third way is connected to one end of the first jumper cap through the first resistor and the sliding rheostat; the other end of the first jumper cap is connected in series with the second capacitor and the fifth resistor and then connected to the positive pole of the power supply; One end of the four resistors is connected between the second capacitor and the fifth resistor connected in series, and the other end is connected to the collector of the first triode through a diode, and is also connected to the base of the third triode; the first triode The emitter of the tube is grounded through the third resistor; the two ends of the second jumper cap are connected in parallel to the two ends of the diode; the base of the second triode is connected between the fourth resistor connected in series and the diode, and the second and third The collector of the pole tube is connected to the positive pole of the power supply, and the emitter is connected to the active end of the sliding rheostat through the sixth resistor, and is also connected to the emitter of the third triode through the seventh resistor; the active end of the sliding rheostat is connected in series The second signal sampling point is drawn after the three capacitors, and the third jumper cap and the load resistor are connected in series and grounded; a light-emitting diode and a current-limiting resistor are directly connected between the positive pole of the power supply and the ground; the ground signal directly leads to the ground signal sampling point; the second The first triode and the second triode both adopt NPN type triode, and the third triode adopts PNP type triode. In the specific experiment, if the voltage gain of the signal needs to be increased, the first jumper cap is connected to the bootstrap circuit; if the crossover distortion of the complementary symmetrical power amplifier circuit needs to be observed, the second jumper cap is connected; if If the load needs to be connected, connect the third jumper cap.

As shown in Figure 10, it is the circuit schematic diagram of the FET amplification experiment circuit of the present utility model: the first signal sampling point is connected in series with the first input resistor, the first jumper cap and the second input resistor and then grounded; the second jumper One end of the cap is connected between the serially connected first input resistor and the first jumper cap, and the other end leads directly to the second signal sampling point, and at the same time connects the first capacitor in series to the gate of the FET, and also passes through the fifth The resistor and the first motor are grounded; one end of the fourth jumper cap is connected between the fifth resistor and the first resistor, and the other end is connected in series with the sliding rheostat and the third jumper cap and then connected to the positive pole of the power supply; the source of the field effect transistor passes through The fourth resistor is grounded; the drain of the FET is connected to the positive pole of the power supply through the sliding rheostat and the third resistor, and the second capacitor is connected in series to lead to the second signal sampling point; the second signal sampling point is also connected through the fifth jump in series The line cap and the third capacitor are grounded afterward, and the second signal is grounded through the sixth signal sampling point connected in series and the load resistor; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground; the ground directly leads to the ground signal sampling point ; The field effect transistor adopts N-channel insulated gate field effect transistor. In the specific experiment, in the normal experiment, the third to fifth jumper caps need to be connected; when the indirect method is used to measure the input resistance, the second jumper cap needs to be connected. When the voltage Vs is too large, the first jumper cap can be connected. One jumper cap; when the load needs to be connected (such as measuring the output resistance of a single-stage amplifier circuit), connect the sixth jumper cap.

As shown in Figure 11, it is the circuit schematic diagram of the differential amplification experiment circuit of the present utility model: one end of the third resistor and one end of the sixth resistor are all connected to the positive pole of the power supply, and the other end of the third resistor directly leads to the first signal sampling circuit, and at the same time Connected to the collector of the first triode, the base of the first triode is grounded through the second resistor and the first resistor, and the first signal sampling point is drawn between the second resistor and the first resistor; the second triode The base of the tube is grounded through the seventh resistor and the tenth resistor, and the second signal sampling point is drawn between the seventh resistor and the tenth resistor; the emitters of the first triode and the second triode are connected at Together; the movable end of the sliding rheostat is connected to one end of the first jumper cap and the second jumper cap at the same time, and the other end of the first jumper cap is connected to the negative power supply through the fourth resistor; the other end of the second jumper cap is connected to the third The collector of the triode, the emitter of the third triode are connected to the negative power supply through the fifth resistor, the base of the third triode is connected to the negative power supply through the ninth resistor, and are also grounded through the eighth resistor; the positive pole of the power supply and A light-emitting diode and an idler resistor are connected between the grounds; the ground directly leads to a ground signal sampling point; the first, second and third transistors are all NPN transistors. During normal experiment, disconnect the first jumper cap and connect the second jumper cap, so that the third triode T3 and its auxiliary circuit constitute a constant current source.

As shown in Figure 12, it is the circuit schematic diagram of the triode unipolar-two-stage-negative feedback amplification experimental circuit of the present utility model: the first signal sampling point is grounded through the first input resistor, the first jumper cap and the second input resistor; One end of the second jumper cap is connected between the first input resistor and the first jumper cap, and the other end of the second jumper cap directly leads to the second signal sampling point, and the first capacitor is connected in series to form three signals: The first signal is connected to the positive pole of the power supply through the sliding rheostat and the first resistor, the second signal is grounded through the third jumper cap and the second resistor, and the third signal is directly connected to the base of the first triode; the first triode The emitter of the tube is grounded through the fourth resistor and the fifth resistor; one end of the fifth jumper cap is also connected between the fourth resistor and the fifth resistor, and the other end of the fifth jumper cap is grounded through the fourth capacitor; the first The collector of the triode is connected to the positive pole of the power supply through the third resistor; the two ends of the third resistor are connected with the fourth jumper cap; the collector of the first triode also passes through the second capacitor to form three signals: the first The first signal directly leads to the third signal sampling point, the second signal is grounded through the seventh jumper cap and the first load resistor, and the third signal is connected to the base of the second triode after passing through the eighth jumper cap; the second The base of the triode is also connected to the positive pole of the power supply through the second sliding rheostat and the tenth resistor, and also grounded through the sixth resistor; the emitter of the second triode is grounded through the eighth resistor and the ninth resistor; the eighth resistor and One end of the ninth jumper cap is also connected between the ninth resistors, and the other end of the ninth jumper cap is grounded through the sixth capacitor; the collector of the second triode is connected to the positive pole of the power supply through the seventh resistor, and also through the fifth The capacitor leads to the third signal sampling point; the third signal sampling point is also grounded through the tenth jumper cap and the second load resistor, and the third signal sampling point is also connected in series through the feedback resistor, the sixth jumper cap, and the third capacitor Connect the emitter of the first triode; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground; the ground directly leads to the ground signal sampling point; the first and second triodes both use NPN type triodes . In the specific experiment, when connecting the triode single-stage amplifier circuit: disconnect the sixth and eighth jumper caps, disconnect the first-stage amplifier circuit from the second-stage amplifier circuit, and disconnect the feedback path; during normal experiments, disconnect The fourth jumper cap is connected to the fifth jumper cap to maintain a large enough magnification; when the indirect method is required to measure the input resistance, connect the second jumper cap; when the voltage Vs is too large, it can be connected to the first jumper cap Divide the voltage; when the load needs to be connected (to measure the output resistance of the single-stage amplifier circuit), connect the seventh jumper cap; when connecting the triode two-stage amplifier circuit: disconnect the sixth and seventh jumper caps, The jumper cap connects the first stage to the second stage amplifier circuit and disconnects the feedback path; during normal experiments, disconnect the fourth jumper cap and decide whether to connect the fifth jumper cap according to the magnification; an indirect method is required When measuring the input resistance, connect the second jumper cap. When the voltage Vs is too large, you can connect the first jumper cap; jumper cap. When connecting the triode negative feedback amplifier circuit: disconnect the seventh and tenth jumper caps, connect the sixth and eighth jumper caps, connect the first stage and the second stage amplifier circuit, and connect the feedback path; during normal experiments, Disconnect the fourth jumper cap, and decide whether to connect the fifth jumper cap according to the magnification.

Claims (10)

1. A kind of analog circuit experimental device for teaching, it is characterized in that comprising power circuit and analog circuit teaching module; Connect or disconnect analog circuit devices, and set signal sampling points at key signal points of the analog circuit signal transmission loop, to quickly extract key analog circuit signals for sampling or to an oscilloscope for observation. 2. The analog circuit experiment device for teaching according to claim 1, characterized in that the signal sampling point is set on the key signal point of the analog circuit signal transmission loop, specifically at the key signal point of the analog circuit signal transmission loop The signal point is led out by a triangular test ring. 3. the analog circuit experimental device for teaching according to claim 1, characterized in that the analog circuit teaching module includes a signal source circuit, rectification-filtering-integrated voltage stabilization experimental circuit, square wave generation experimental circuit, RC Sine wave oscillation experimental circuit, integrated power amplification experimental circuit, integrated operational amplifier experimental circuit, complementary symmetrical power amplification experimental circuit, field effect tube amplification experimental circuit, differential amplification experimental circuit and triode unipolar-two-stage-negative feedback amplification experimental circuit. 4. The analog circuit experiment device for teaching according to claim 3, characterized in that said rectification-filtering-integrated voltage stabilizing experimental circuit comprises a step-down transformer, a rectifier bridge, and a filter circuit with a common ground terminal on the secondary side , voltage regulator chip, output filter and load; the common ground terminal of the secondary side of the step-down transformer is grounded; the output of the secondary side of the transformer is rectified by the rectifier bridge to obtain positive and negative two-way power signals, and then filtered by their respective filter circuits to obtain two A stable DC current signal is input to two voltage regulator chips, and the output terminals of the two voltage regulator chips output one positive power supply and one negative power supply respectively, and output a stable voltage signal after being filtered by the output filter; among them, the output of the rectifier bridge A first jumper cap is set on the positive bridge arm, a second jumper cap is connected in series at the output end of the rectifier bridge and leads to the first signal sampling point, between the output end of the filter circuit and the input end of the voltage regulator chip A third jumper cap is also connected in series and leads to the second signal sampling point, and a fourth jumper cap is connected in series after the filter circuit at the output negative end of the rectifier bridge and leads to the third signal sampling point. The output terminals of the output lead respectively to the fourth signal sampling point and the fifth signal sampling point; the load includes the first load resistor, the second load resistor and the sliding rheostat, and the output terminal of the first voltage regulator chip passes through the fifth jumper cap, the second A load resistor, the sliding rheostat, the second load resistor and the sixth jumper cap are connected to the output end of the second voltage regulator chip, and the sliding end of the sliding rheostat is grounded, and the sixth signal sampling point is also drawn out. 5. the analog circuit experiment device that is used for teaching according to claim 3 is characterized in that described integrated power amplification experimental circuit comprises the integrated power amplifier that model is LM386; 3 pins of integrated power amplifier draw the first signal sampling point , pin 2 and pin 4 are grounded, pin 1 is connected to pin 8 through the bootstrap capacitor and the first jumper cap, pin 7 is grounded through the filter capacitor, pin 6 is connected to the positive pole of the power supply, and also grounded through the power filter capacitor, and also through current limiting The resistance and the LED indicator light are grounded, and pin 5 is the output pin, which leads to the second signal sampling point after passing through the filter capacitor, and also grounds through the RC circuit, and also grounds through the second jumper cap and the speaker; the ground signal leads to the third signal Sampling point. 6. the analog circuit experiment device for teaching according to claim 3, it is characterized in that described integrated operational amplifier experimental circuit comprises the operational amplifier chip that model is LM741; 4 pins of chip are connected power negative pole, 7 pins are connected power supply Positive pole, pin 6 is the output terminal, which leads directly to the sixth signal sampling point; one end of the first jumper cap is connected to the output terminal of the chip, and the other end is connected to pin 2 of the chip, and at the same time leads to the first signal sampling point through a broken wire; the second jumper cap One end of the wire cap is connected to the output terminal of the chip through the second capacitor, and the other end is connected to pin 2 of the chip, and the second signal sampling point is also drawn out through the first capacitor; one end of the third jumper cap is connected to the output of the chip through the first resistor One end of the fourth jumper cap is connected to the output end of the chip through the third resistor, and the other end is connected to pin 2 of the chip. The fourth resistor leads to the fourth signal sampling point; pin 3 of the chip is the positive input pin, which leads to the fifth signal sampling point through the fifth resistor, and is also grounded through the sixth resistor; the ground signal directly leads to the ground signal sampling point. 7. The analog circuit experimental device for teaching according to claim 3, characterized in that in the complementary symmetrical power amplification experimental circuit, the first signal sampling point is divided into three paths after the first signal sampling point passes through the first capacitor, and one path passes through the second The resistor is grounded, the second path is connected to the base of the first triode, and the third path is connected to one end of the first jumper cap through the first resistor and the sliding rheostat; the other end of the first jumper cap is connected in series with the second capacitor 1. Connect the positive pole of the power supply behind the fifth resistor; one end of the fourth resistor is connected between the second capacitor connected in series and the fifth resistor, and the other end is connected to the collector of the first triode through a diode, and also connected to the third and third The base of the first triode; the emitter of the first triode is grounded through the third resistor; the two ends of the second jumper cap are connected to the two ends of the diode; the base of the second triode is connected to the first Between the four resistors and the diode, the collector of the second triode is connected to the positive pole of the power supply, and the emitter is connected to the active end of the sliding rheostat through the sixth resistor, and at the same time continues to be connected to the emitter of the third triode through the seventh resistor. Pole; the movable end of the sliding rheostat is connected in series with the third capacitor to lead to the second signal sampling point, and at the same time connected in series with the third jumper cap and the load resistor and then grounded; a light-emitting diode and a current-limiting resistor are directly connected to the positive pole of the power supply and the ground; The ground signal is directly led to the sampling point of the ground signal; both the first triode and the second triode are NPN transistors, and the third triode is a PNP transistor. 8. The analog circuit experiment device for teaching according to claim 3, characterized in that in the field effect tube amplification experiment circuit, the first signal sampling point is connected in series with the first input resistor, the first jumper cap and the first After the second input resistor is grounded; one end of the second jumper cap is connected between the serially connected first input resistor and the first jumper cap, and the other end directly leads to the second signal sampling point, and at the same time, the first capacitor is connected in series and then connected to the field effect The grid of the tube is also grounded through the fifth resistor and the first motor; one end of the fourth jumper cap is connected between the fifth resistor and the first resistor, and the other end is connected in series with the sliding rheostat and the third jumper cap. The positive pole of the power supply; the source of the FET is grounded through the fourth resistor; the drain of the FET is connected to the positive pole of the power supply through the sliding rheostat and the third resistor, and the second capacitor is connected in series to lead to the second signal sampling point; the second signal The sampling point is also grounded through the fifth jumper cap and the third capacitor connected in series, and the second signal is grounded through the sixth signal sampling point connected in series and the load resistor; a light-emitting diode and an idler are connected between the positive pole of the power supply and the ground resistor; the ground directly leads to the sampling point of the ground signal; the field effect transistor uses an N-channel insulated gate field effect transistor. 9. The analog circuit experimental device for teaching according to claim 3, characterized in that in the differential amplification experimental circuit, one end of the third resistor and one end of the sixth resistor are connected to the positive pole of the power supply, and the other end of the third resistor One end leads directly to the first signal sampling circuit, and at the same time connects to the collector of the first triode, the base of the first triode is grounded through the second resistor and the first resistor, and at the same time leads out between the second resistor and the first resistor The first signal sampling point; the base of the second triode is grounded through the seventh resistor and the tenth resistor, and the second signal sampling point is drawn between the seventh resistor and the tenth resistor; the first triode and the second three The emitters of the pole tubes are connected together through a sliding rheostat; the movable end of the sliding rheostat is connected to one end of the first jumper cap and the second jumper cap at the same time, and the other end of the first jumper cap is connected to the negative power supply through the fourth resistor; The other end of the second jumper cap is connected to the collector of the third transistor, the emitter of the third transistor is connected to the negative power supply through the fifth resistor, and the base of the third transistor is connected to the negative power supply through the ninth resistor. It is also grounded through the eighth resistor; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground; the ground directly leads to the ground signal sampling point; the first, second and third triodes all use NPN type triodes . 10. The analog circuit experimental device for teaching according to claim 3, characterized in that in the described triode unipolar-two-stage-negative feedback amplification experimental circuit, the first signal sampling point passes through the first input resistance, the first The jumper cap and the second input resistor are grounded; one end of the second jumper cap is connected between the first input resistor and the first jumper cap, and the other end of the second jumper cap directly leads to the second signal sampling point, and is connected in series After the first capacitor, three signals are formed: the first signal is connected to the positive pole of the power supply through the sliding rheostat and the first resistor, the second signal is grounded through the third jumper cap and the second resistor, and the third signal is directly connected to the first three The base of the pole tube; the emitter of the first triode is grounded through the fourth resistor and the fifth resistor; one end of the fifth jumper cap is also connected between the fourth resistor and the fifth resistor, and the fifth jumper cap The other end is grounded through the fourth capacitor; the collector of the first triode is connected to the positive pole of the power supply through the third resistor; both ends of the third resistor are connected with the fourth jumper cap; the collector of the first triode is also connected to the positive pole of the power supply through the third resistor. Three signals are formed after the two capacitors: the first signal directly leads to the third signal sampling point, the second signal passes through the seventh jumper cap and the first load resistor to ground, and the third signal passes through the eighth jumper cap and then connects to the first The base of the second triode; the base of the second triode is also connected to the positive pole of the power supply through the second sliding rheostat and the tenth resistor, and also grounded through the sixth resistor; the emitter of the second triode is connected through the eighth resistor One end of the ninth jumper cap is also connected between the eighth resistor and the ninth resistor, and the other end of the ninth jumper cap is grounded through the sixth capacitor; the collector of the second triode is connected through the seventh The resistor is connected to the positive pole of the power supply, and the third signal sampling point is also led out through the fifth capacitor; the third signal sampling point is also grounded through the tenth jumper cap and the second load resistor, and the third signal sampling point is also connected in series through the feedback resistor Connect the emitter of the first triode with the sixth jumper cap and the third capacitor; a light-emitting diode and an idler resistor are connected between the positive pole of the power supply and the ground; the ground directly leads to the ground signal sampling point; the first and The second transistors are all NPN transistors.