Effective Teaching Design Based on the Combination of BOPPPS Model and Tina Virtual Simulation Software

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Introduction
Efective teaching design plays a vital role in improving teaching quality. With the rapid development of information technology and computer technology, many advanced teaching concepts were used in teaching design. Especially, with the wide application of online resources, online and ofine mixed teaching mode is widely used in teaching. Teachers are concerned about how to integrate information technology with the advanced teaching concepts to better promote the teaching quality. Virtual simulation technology makes full use of various information technologies and plays an important role in modern teaching modes. Tina, as a computer-aided virtual simulation software, contains about 20000 discrete or integrated circuit components. Usually, it can design and simulate various complex analog circuits and digital circuits. Its main functions include direct-current analysis, transient analysis, sinusoidal steady-state analysis, temperature scanning, fourier analysis, and parameter scanning. In the actual application, the software plays high-efciency and high-precision role in the development of electronic products. So, it is very suitable for simulating various analog and digital circuits. Tina interface is shown in Figure 1. In the interface, it is convenient to draw graphics, and students can observe the simulation results intuitively, so that the corresponding conclusions can be obtained based on the simulation results. With the help of Tina virtual simulation software, students can combine theory and practice more closely, thus promoting the teaching quality.
Recently, many scholars have made some gratifying achievements by using the Tina software. Wu et al. [1] introduced a noise suppression network with automatic adjustable parameters by Tina software. Derkaoui et al. [2] used the Tina software to simulate the forward converter. Zhang and Huang [3] built a heart sound signal and proved that good teaching efect can be achieved through virtual simulation analysis. Meng et al. [4] applied Tina software to simulate heat conduction problems, the results showed the satisfactory results. Te above mentioned references have achieved certain results using the Tina software. However, most of them do not discuss the characteristics of Tina software. Tey do not achieve results by improving the circuits layer by layer. In fact, Tina software has a powerful simulation function [5], while it has more obvious advantages in simulating analog electronic circuits and digital electronic circuits. So, it needs to formulate efective teaching design based on the characteristics of the software and course. In this article, we used the Tina software to gradually improve the amplifer circuit in analog electronics technology course. Te proposed method can better improve the teaching design quality.
On the other hand, in order to further develop teaching quality, efective teaching design is essential. BOPPPS model is considered as an "efective," "efcient," and "benefcial" teaching model. It is created by the Canadian teacher skills training workshop [6]. Te model includes six parts: bridgein, objective, preassessment, participatory learning, postassessment, and summary. BOPPPS comes from the acronyms of English words in each part. Its meaning of each part is shown in Figure 2.
BOPPPS model emphasizes the students' participation and feedback. It can provide good teaching results and improve the satisfaction of learners [7]. Furthermore, it is very benefcial to promote students' deep learning and apply the related skills to solve the practical problems. Besides that, it is useful to improve the teaching quality by actively exploring the innovation and reform. It also provides teachers to guide the teaching design and makes teaching design more reasonable and scientifc.
We developed the teaching design based on BOPPPS model and Tina virtual simulation software. Its structure is as follows: Section 2 presents the triode amplifer circuit teaching design based on BOPPPS model and Tina simulation software. In this process, the circuits are simulated using a step-by-step questioning method. In the meantime, fipped classroom is used to further promote teaching reform. Section 3 presents the teaching efects. In Section 4, the discussion and conclusion are presented in detail.

Effective Teaching Design Based on BOPPPS Model and Tina Virtual Simulation Software
Recently, virtual simulation technology was introduced to assist theoretical teaching and experiments. Tina software can intuitively and vividly show the simulation results to students. Te simulation results are helpful to stimulate students' enthusiasm and subjective initiative. In order to better carry out teaching design according to the six parts of the BOPPPS model, we used BOPPPS model as the foundation and used Tina virtual simulation software as the auxiliary tool.

Bridge-In.
Interestingly bridge-in will attract students' attention and improve their learning interest. Students can know the theme and importance of learning content according to the bridge-in. Bridge-in can be performed by pictures, videos, or real objects. Te triode amplifer circuit is the basic unit of a complex circuit. At present, many electronic systems need amplifer circuits, such as mobile phones, radios, loudspeakers, and stethoscopes. Tese devices are closely connected with students and can inspire their learning interest more.

Objective.
Teaching objective enables students to understand the requirements that they need to achieve. It is the interaction between teaching and learning. Teaching design is always guided by teaching objective. Teaching objective includes knowledge objective, ability objective, and value objective. Teacher should clearly point out the knowledge objective. Ability objective is refected by using Tina software to simulate and design circuits. Value objective refers to the pursuit and aspiration of students, which is obtained by group discussions, fipped classroom, and electronic production display. Table 1 shows the teaching objective of the triode amplifer circuit.

Preassessment. Preassessment mainly assesses students'
prior knowledge and helps the teacher to adjust the teaching strategies based on the preassessment results. In this process, it is necessary to master the real cognition of students.
To learn the triode amplifer circuit, student must master the working areas of triode. Working areas include three areas such as amplifcation area, cut-of area, and saturation area. Te output characteristic of a triode amplifer circuit and its simulation result based on Tina virtual software is shown in Figure 3. Tina software has the ability to perform DC analysis, AC analysis, and transient analysis [8]. So, it is useful to facilitate students to better understand the relevant circuit.
Special note: the horizontal coordinate of simulation diagrams from Figures 3 to 8 is time (unit in S), and the vertical coordinate is voltage or current (unit in V or A). Besides that, due to Tina software limitations, the u and U, as well as I and i, involved in the fgures of this article are not distinguished.

Participatory Learning.
As the core of BOPPPS model, participatory learning takes students as the centre, encourages students to actively participate, exchange information and feedback between teachers and students, so that students can deeply apply knowledge to practice. In this process, the teacher may design multiple interactive strategies such as group discussions or individual reports. It is advantageous for promoting students to learn actively, think deeply, and innovate actively. In this article, we improved the students' participatory learning ability by gradually improving various amplifer circuits.       intuitively display each waveform and value. It is benefcial for students to master relevant knowledge. Te circuit of Figure 4(a) is simple and adjustable. However, external factors such as temperature change, triode aging, and voltage fuctuation will change the triode static working point. If this point is set inappropriately, it will make the circuit work improperly and cause waveform distortion. In order to reduce these unstable factors, the improved circuit is shown in Figure 5 Scientifc Programming in Figure 4(a) under the same parameters. Simulation conclusion is consistent with the theoretical analysis. Te common emitter amplifer circuit has the capability of voltage amplifcation and current amplifcation. Do all circuits have the characteristics? Te common base amplifer circuit is introduced by setting this question.
Te direct-current path and waveforms of Figure 6(a) is same as Figure 5(a) under the same parameters, so the waveforms of static working point are not shown in Figure 6(b). Figure 6(b) realizes the in-phase voltage amplifcation.
Te common base amplifer circuit has the voltage amplifcation ability. Besides that, it has the characteristic of the current follower. Can the circuit achieve the voltage following capability? Subsequently, the common collector amplifer circuit is introduced by setting this question.
Te static working point of Figure 7(a) is similar with Figure 4(a), so it does not simulate it in Figure 7(b). Figure 7(b) shows that the voltage gain is close to 1. It indicates that the circuit has a voltage following efect. So, it is called a voltage follower.
From Figures 4 to 7, we can obtain the conclusions shown in Table 2.
In the teaching process, it is very important to cultivate students' ability to solve practical problems. Next, the teaching design will be launched based on how to eliminate the circuit distortion.
Reasonable static working point can ensure the amplifer circuit to work well. However, this point may cause the nonlinear distortion due to the changes in the external environment. In Figure 8, it can observe the saturation distortion, cut-of distortion, and large signal distortion by setting diferent circuit parameters.
(a) If the signal amplitude of vi is set to 5 mv and Rb is set to 100 kΩ, the static working point is too high. It will cause the saturation distortion shown in Figure 8(b). Of course, the distortion can be eliminated by increasing the Rb value. (b) If the signal amplitude of vi is set to 45 mv and Rb is set to 500 kΩ, the static working point is too low. It will cause the cut-of distortion shown in Figure 8(c). Of course, the distortion can be eliminated by reducing the Rb value. (c) If the signal amplitude of vi is large, such as 500 mv, and other parameters remain unchanged, it will cause the large signal distortion shown in Figure 8(d). Of course, it may reduce the input signal amplitude to avoid the large signal distortion.
Furthermore, in order to further embody participatory learning, it may set the fipped classroom. Flipped classroom can improve the teaching quality according to the diferent characteristics of the students and teach students according to their aptitude in diferent levels [9]. Besides that, it brings students to develop their own self-learning strategies to adapt to the demands of the learning environment. Some researchers have achieved some results using fipped classrooms [10][11][12][13][14]. In many references, most students explain knowledge according to the teacher's requirements. Te introduced course requires the combination of theory and practice, which refects more aspects of students' innovative and practical abilities. So, the introduced fipped classroom mainly refects the gradual improvement of students' circuitry, fnds and solves practical problems, and gradually improves their comprehensive abilities such as practical innovation and group cooperation. Te fipped classroom is very welcoming among students.
In this article, the basic requirements of the fipped classroom include the following points: ① Master circuit characteristics, circuit working principles, circuit calculation methods, and circuit application areas. ② Use the Tina virtual simulation software adroitly, apply the software to build circuits, simulate circuits, analyze circuits, and design practical circuits. ③ Upload simulation results to the MOOC platform. Recently, online and ofine mixed teaching mode become an important trend of teaching development under the background of "Internet +" [15]. Students not only can participate in the mutual evaluation on the MOOC platform, but also improve their own circuits by fnding the advantages of other circuits. ④ If there is a circuit distortion phenomenon, how to eliminate the distortion. Tis method can cultivate students' ability to discover problems and solve practical problems.
(c) Additional points: simulate circuits that can stabilize the static working point. Tis process is conducive to hierarchical teaching based on students' learning situations. It can cultivate exploration, collaboration, and innovation abilities for students.
Te fipped classroom is conducive to integrate theory with practice. It promotes students to participate in learning and improves students to solve the practical problem ability. Besides that, group discussion can encourage students to actively think, analyze, compare, judge, test, communicate, and cooperate. Tese aspects are conducive to cultivate students' deep understanding of team spirit and cooperation consciousness, and help them to achieve value objective.

Postassessment.
Postassessment is benefcial for the teacher to master students' learning efects, and further improve the teaching design ability. Postassessment can be conducted by asking questions, questionnaire survey, homework, and test. In this article, postassessment allows students to observe the characteristics of distortion waveform and master some methods of elimination distortion. In addition, it may encourage students to fnish the Table 3.

Scientifc Programming
2.6. Summary. Summary is to succinctly summarize the knowledge points, sort out, and review the teaching contents to further consolidate the teaching objective. In this article, teacher guides the students to summarize the circuit characteristics according to the circuit simulation results. In the meantime, the teacher may comment and replenish the relevant contents. In this stage, teacher may arrange preview tasks and provide some pertinent websites and materials. Tis method is useful for further cultivating students' ability to consult documents and materials.
BOPPPS teaching model can provide a complete teaching framework for teachers [16]. Tina virtual simulation software connects theory with practice more closely. Te combination of BOPPPS model and Tina virtual simulation software benefts teachers and students more.

Effects
Combination of BOPPPS model with Tina simulation software can efectively improve the teaching quality. Te efects can be considered from both the students and teachers. We tested the students in two classes. Te number of students before the reform is 126, and the number of students after the reform is 113. Te distributions of the test scores are shown in Table 4. Table 4 shows that the scores after reform are generally higher than those before reform. For the before reform class, the number of students with a score of 90 to 100 is 11, its proportion is 8.7%, and the number of students with scores of less than 60 is 14, its proportion is 11.1%. While for the after reform class, the number of students with score of 90 to 100 is 12, its proportion is 10.6%, the proportion of high score students has increased by 1.9% than before reform class, and the percentage of students with scores ranging from 80 to 89 has increased by 11.9% compared to before reform class. Besides that, all test scores exceed 60.
Moreover, students' electronic technology simulation capabilities and practical abilities have been efectively improved. Tey obtain better results when making electronic products. Tey actively participated in competitions and have achieved many outstanding results in the National Undergraduate Electronic Design Competition and National College Student Smart Car Competition. Teachers have also achieved excellent results. Tey participated in the teaching competition and won the frst prize. Tey obtained many educational reform projects and published many teaching reform articles. Furthermore, the introduced course has been awarded many honorary titles such as provincial-level online frst-class course, provincial-level online and ofine mixed frst-class course, and provincial-level top quality online open course. In summary, these achievements indicate that the proposed method is an efective teaching reform.

Discussion and Conclusion
As an efective teaching design model, BOPPPS provides a theoretical basis for teaching design. In practical applications, the six elements of BOPPPS model are not fxed. Te sequences can be appropriately changed according to the characteristics of the curriculum contents and teachers. Besides that, it may comprehensively consider the teaching situation and students' learning level, and fexibly use the model to formulate an efective teaching design based on the course characteristics. In addition, according to the course characteristics, we introduced many practical circuits using the Tina virtual simulation software step-by-step. Te introduced method makes teaching design ideas clearer and combines theory with practice more closely. However, since Tina software is suitable for designing small-scale circuits. As for complex circuits, it needs to further develop the Tina software characteristics to better meet the needs of practical  8 Scientifc Programming circuit simulation and teaching design. In fact, according to the proposed method, students' enthusiasm for learning and practical ability can be efectively promoted by asking questions layer-by-layer. Moreover, fipped classroom encourages students to analyze and design circuits, cultivate and improve thinking ability and analyzing practical problems independently, mobilize their learning enthusiasm, and enhance their innovative consciousness. In a word, efective teaching design based on the combination BOPPPS model with Tina virtual simulation software will play an important practical signifcance for promoting the teaching reform and development.
Generally speaking, we fnd that small-class teaching may present better results than large-class teaching. In future, we will further explore how to better utilize the proposed method in large-class teaching to achieve better teaching results. Besides that, we will also expand the scope of our research and collect more feedback information to further provide a more scientifc basis for teaching reform.

Data Availability
Te data used in this study are available from the author upon request.

Conflicts of Interest
Te authors declare that they have no conficts of interest.