Tim Jackson - University of Birmingham
Steve Quigley - University of Birmingham
About Our Undergraduate Degree Programmes
The School of Engineering at the University of Birmingham in the United Kingdom recently began offering six entry streams to undergraduate degrees: civil, electrical and electronic, electrical and railway, civil and railway, mechanical, and general engineering. The 370 enrolled students share a common first year, before their area of specialisation is fixed.
Students enter the course with advanced-level school qualifications in mathematics, typically taken at age 18. Some students have not studied science since they were 16 years old. The entry-level course in electrical engineering includes analysis and applications of analogue and digital circuits. This is a year of discovery and exploration; we need to help students gain the background knowledge needed within the limited hours of practical classes. Ultimately, this prepares the students for their subject-specific second year, when they experience most of the core degree accreditation technical material. We need robust and intuitive equipment to use in the laboratory to accelerate the student learning experience. Also, the equipment vendor must provide service agreements for rapid repair or replacement of the technology to mitigate downtime and extra expenditure.
In previous years, we used separate box instruments for the introductory electronics labs delivered to 90 electrical engineering students. Although the students had extended lab time, they used traditional equipment. Many still struggled with instrument functionality, such as providing opposite polarity power rails for op-amps or using advanced measurement functions on the oscilloscope. Students also found it difficult to grasp time base and triggering selection concepts using the older box instruments. We realised there was a problem with the way the students engaged with the equipment.
These challenges led us to change to the VirtualBench all-in-one instrument a year before the onset of the large cohort, because it was evident that our students needed a more intuitive and user friendly instrumentation platform.
Why We Chose VirtualBench
We debated within the department on the educational merits of an all-in-one platform like VirtualBench compared with fixed-functionality instruments with traditional knob and button interfaces. Which would be more intuitive? Which would be more representative of the near-future workplace for new graduate engineers? After consultation with colleagues, including recent graduates, we thought the old equipment was dated. While familiar to us as lecturers, it was not in keeping with the field test equipment we believed our graduates would use in the future.
How to Teach Our Students
The learning experience begins with introductory materials starting from high school level electronics. We point them to “Getting Started With VirtualBench” videos on YouTube, to encourage a connection between real-world measurements and theoretical understanding. Students can take multiple choice gateway quizzes that include theory, getting started with VirtualBench, and some health and safety. We want to encourage the integration of theoretical understanding with practical skills and critical thinking, because these are key attributes of a professional engineer.
Students use the powerful, yet intuitive, VirtualBench software interface, which appears as soon as the instrument connects to a PC via USB cable. They use built-in functionality, like signal averaging and cursor measurements, to extract meaningful data from the waveforms. The presence of other instruments on the same screen, like a digital multimeter and oscilloscope, shows a direct comparison of important parameters such as the peak amplitude and root mean square of a waveform.
The key VirtualBench features leveraged in our laboratory classes within the wider learning activities include:
• AC and DC voltage acquisition and analysis to understand the difference between peak and rms values of sinusoidal, square, and triangle waves
• The function generator to explore DC offset modes and the use of sinusoidal and square waves
• The oscilloscope to explore the probe x10 function, AC and DC operation, bandwidth limiting, the time base, the difference between peak and peak-to-peak amplitudes, and cursor and direct screen measurements
• Built-in signal averaging to remove random noise
• The DC power supply for single and dual polarity power supplies
• The interface to log data for electronic record keeping
In later first-year classes, students begin to move away from the ready-made VirtualBench interface, using LabVIEW to develop their own software interfaces for custom analysis and data logging.
VirtualBench: A Student Perspective
We questioned six students for their thoughts on the new lab experience.
• Several students commented that VirtualBench was easier to learn than the legacy equipment.
• All had struggled with the traditional oscilloscopes, with hidden menus and misleading labels partly to blame.
• All students felt the previous introductory labs left them with gaps in knowledge that took years to fill.
• A first-year student, who had used separate test equipment in electronics in high school, found the VirtualBench easier to understand and use. Two experienced students mentioned functions such as Fourier Analysis, dual-mode display on the oscilloscope and over current warnings as being easier to access.
• All students feel more confident working with a software interface that utilises symbols they know from other devices. They can easily recognise and find appropriate functionality and feel less afraid of causing damage.
• The teaching assistants, who collectively hold over 16 years of lab class experience, find trouble shooting on VirtualBench easier; thus, giving them more time to develop student understanding.
We have noticed that more senior students who had no training on the VirtualBench are starting to prefer it to the legacy equipment that they were trained on. They use it as a stand-alone instrument and program using LabVIEW to run experiments and record data.
VirtualBench: A Staff Perspective
Since the adoption of VirtualBench, we found a dramatic reduction in equipment downtime, with fewer experiments failing because of faulty equipment. This reduces the workload of lab technicians and raises the value of the students’ lab time. Although we have had zero faults with VirtualBench, the NI service contract with rapid repair turnaround was a key factor in our adoption of VirtualBench. We used VirtualBench to accelerate the teaching of electronics to undergraduate students in a much more intuitive and engaging way, which was not possible using conventional benchtop instrumentation.
We will introduce electronic lab books to this course. We want to have an automatic marking system that assesses the students’ theoretical calculations with the data they captured/exported from their VirtualBench instruments. We also plan to move to a new Collaborative Teaching Laboratory soon. Students from widely different degree courses, not just engineering and science, can use this space. We need non-specialists to be able to access the functionalities of the test equipment provided. Our experience with VirtualBench gives us confidence that this is achievable. As the lab desks become hot desks, we need equipment that can stay in place for different classes to maximise the time the space is used productively. The significant reduction in footprint (see Figure 2 and Figure 3) will be invaluable.
University of Birmingham