Using a web-based and stand-alone oscilloscope for physics experiment during Covid-19 pandemic

As with all science curricula, physics emphasizes the development of both the content knowledge and the procedural understanding. It is achieved through hands-on activities in the laboratory, where the students are able to control the experiment and have experience with the scientific instruments. By 'seeing and doing', they acquire the content and practical knowledge more quickly and thoroughly. One of the fundamental components of students' learning is to develop the practical skills through laboratories and practical classes, especially in physics and engineering. An oscilloscope is a basic measuring instrument used to study all types of waveforms and time-varying electric signals. In our situation, at the pre-university level, an oscilloscope not only enables students to measure the voltage, but it is also used to quantify the measurements related to electrical signals such as peak-to-peak voltage, V_pp, frequency, f, amplitude, A, period, T, phase difference, Δϕ, and pulse width, PW. An oscilloscope is able to display both periodic and non-periodic signals. Hence, it allows students to 'see' and study electric and wave signals comprehensively.

However, students perceive the oscilloscope as a difficult measuring instrument, mainly due to the lack of opportunities to practice its usage [1]. In some cases, this is due to the inadequate number of oscilloscopes and signal generators in schools [2]. Many reported alternatives have been suggested, such as the use of pc sound card [3, 4], a low-cost AC experimental package [5, 6], and even virtual oscilloscope [7] but most of the alternatives are more suitable for students with some background knowledge in science and engineering. At the introductory-level physics, they find it hard to understand the basic principles of an oscilloscope because they still require a moderate level of supervision from the instructor. This has become even more difficult as the mode of instruction has migrated to online teaching. As an alternative, we discuss a useful web-based and stand-alone oscilloscope that can be used or downloaded at [8]. This is a complete simulated set-up which consists of a low-frequency (signal) generator (LFG), a direct current power supply, and an oscilloscope. The web-based and stand-alone oscilloscope can be utilized as a simulation for school students and as an alternative to face-to-face lab activity for pre-university students. The simulation is undoubtedly beneficial for teacher demonstrations and for students to make their own measurements as it also includes LFG which produces alternating current (ac) and power supply which produces direct current (dc) as shown in figure 1.

Zoom In Zoom Out Reset image size

In this simulation, the oscilloscope displays the waves produced by the LFG or power supply. Due to its expensive price, schools are lacking of this type of instruments, especially the schools with poor facilities. Besides that, some oscilloscopes could have additional features apart from their fundamental use that makes novice students not be able to acquire the sufficient competency. This web-based and stand-alone oscilloscope will benefit students as it only concentrates on the most basic parts of an oscilloscope.

The simulation was developed due to the challenge that the simulation's developer [8] has encountered throughout his teaching career. Mostly, he taught physics without physics laboratories, or in best cases, the schools are lacking of crucial equipment, such as oscilloscopes, frequency generators, ripple tanks, etc. To overcome the problems, initially, he used Adobe Flash/ActionScript to code and design many simulated virtual experiments. One of them is the web-based and stand-alone oscilloscope. This version of the oscilloscope simulation is the upgrade version that uses HTML5/JavaScript with Adobe Animate as the development environment due to the fact that flash plugin is no longer supported by major web browsers. In the new version, a dc power supply has also been added and it enables users to simulate experiments that are not present in the older version.

This lab is divided into three parts: (a) a computer simulation that shows the basic operation of the functions of the LFG and the oscilloscope, (b) some simulated simple laboratory measurements that are carried out using an oscilloscope, and (c) an investigation of different ac waveforms. The oscillating input signal is produced by an LFG as shown in figure 2. This simulated LFG enables students to produce any output signals by changing the frequency or amplitude of the LFG. The characteristics of the output signal are already known and shown on the screen of the LFG. With these known values, students have the opportunities to practice and enhance their understanding about the basic usage of an oscilloscope.

Zoom In Zoom Out Reset image size

The signal is captured by the oscilloscope, and it can utilize two input signals via channels 1 and 2 simultaneously, similar to any physical oscilloscope as shown in figure 3.

Zoom In Zoom Out Reset image size

On the oscilloscope, there are two important settings that students need to manipulate, to maximize the signal; the V/div setting (Y-gain) which sets the scale of the vertical axis, and the time/div setting (time-base) that sets the horizontal setting. In this activity, the students have the freedom to control either the amplitude or frequency of the input signal and then they can maximize the signal using the right setting on the oscilloscope. In this simulation, students also have the opportunity to utilize both channels and investigate two input signals concurrently.

In this contribution, a virtual experiment using a web-based and stand-alone oscilloscope for carrying out a physics experiment during the Covid-19 pandemic had been demonstrated and discussed. The web-based and stand-alone oscilloscope is free and can be used either online or offline. Thus, it is a viable alternative to a laboratory practical during the pandemic period or even can be utilized as an effective classroom demonstration. More importantly, the web-based and stand-alone oscilloscope provides a new learning opportunity for students both in experimental methods as well as in data analyses.

We gratefully thank the RMIC, Universiti Pendidikan Sultan Idris (UPSI) (2021-0214-103-01) for the support and encouragement of this project.

All data that support the findings of this study are included within the article (and any supplementary files).