### S1-SP4-1 - Experienced students’ errors in electrical engineering

3. Research Work In ProgressElena Trotskovsky

^{2}, Andrei Cristinel Cziker

^{1}

^{1}Technical University of Cluj-Napoca,Cluj, Romania

^{2}ORT Braude Academic College of Engineering, Karmiel, Israel

**Introduction**

This Research WIP paper presents the analysis of the results obtained during the evaluation period of the first semester 3

^{rd}year B.Sc. students (Electrical Engineering Faculty) at a specialized course and discusses the possible causes of the errors made by the students and the pedagogical efforts that will be made to prevent the misunderstandings that caused these errors.

The engineering educators who teach advanced courses of third – forth years of engineering program for B.Sc degree usually suppose that their students already have basic conceptual knowledge required for their course. But during the course and even in the final exam they discover that the students make principal errors that testify about serious lack of conceptual knowledge. These errors appear every year among the new students of the course, and experienced educators can describe and predict them before the beginning of the course.

An experienced lecturer with 14 years of pedagogical practice in the field of engineering education has been teaching the course "Electrical Energy Usage" during six last years – one course per year. The course consists of two hours of lectures each week and four hours of lab each two weeks. The course involves the issues related to illumination, heating and welding, and protection of electrical devices. In the end of the course the students have theoretical and practical exams. During the lab part of the course the students use the book of lab assignments, which includes all learning materials: electrical schemes, operating instructions, formulas, tables, requirements to draw graphs and conclude. In the practical exam the students are required to create, draw and assemble the circuit of illumination and heating devices, contained specific types of lamps (heating devices: microwave oven and infrared sources) supplied from the AC power network. The circuit must include measurement instruments, such as ammeter, voltmeter and wattmeter. The exam assignments are a little different and more complicated than the standard assignments from the book, as the students must use parts of the circuits learned during the lab. After the circuit assembling the teacher checks it and asks the students questions. She paid attention that from year to year part of the students answer "Yes" on the question “Is it possible to measure active power in your circuit be ammeter and voltmeter?”. The standard explanation was "Because power is the current multiplying by the voltage". This answer is correct in a DC circuit, but in the AC circuit (active power relationship is

*P*=

*V*·

*I*·cos

*φ*,

*V*-voltage,

*I*-current,

*φ*– phase shift between the voltage and current). Therefore, the students forget about phase shift and cos

*φ.*Thus, the research aim is to understand the students’ errors that frequently are the result of misunderstandings.