IEEE Circuits and Systems Magazine - Q3 2021 - 66

Education
By Lino Sousa, André Rocha, Mário Alves, and Francisco Pereira,
Instituto Superior de Engenharia (ISEP), Politécnico do Porto,
Email: sss,anr,mjf,fdp@isep.ipp.pt
U=RIsolve: A Web-Based Application for
Learning Electrical Circuit Analysis
Abstract
Learning circuit analysis is often a challenging issue for Electrical
Engineering undergraduate students. During the course's
early stages, procedures such as the correct identification of
Branches, Nodes and Loops, the expression of Kirchhoff Current
and Voltage Laws, as well as the application of analysis/
simplification Theorems and Algorithms, usually embed tricky
and error-prone steps for beginners. While circuit simulators offer
a validation for theoretical and experimental analysis, they do
not explain how to obtain the results nor the fundamental laws
supporting them. In this regard, a new web-based framework, -
dubbed U=RIsolve (read as " you resolve " ) - for teaching and
self-learning the Node Voltage Method (NVM) is presented in
this paper. The U=RIsolve application goes far beyond the capabilities
of traditional circuit simulators, as it outputs the fundamental
circuit information, the methodology, the equations and
the results related to the NVM. An outlook of the application main
features, user interface and usage in electrical circuit analysis is
provided, along with the future implementations.
I. Introduction
C
ircuit analysis is an introductory subject of most
Electrical Engineering degrees, and it involves
the study of a wide range of circuit laws, theorems
and fundamental concepts that prove to be crucial
for continuous success throughout the course. These
typically include the " baseline " Branch Currents Method,
based on the Kirchhoff's Current Law (KCL) and Kirchhoff
Voltage Law (KVL), the Superposition Theorem Method,
the Mesh-Current Method (MCM) and the Node Voltage
Method (NVM). The MCM is particularly appealing for
analysing complex circuits with more Nodes and fewer
Branches, while NVM suits better for circuits with more
Branches and fewer Nodes, reducing the number of
equations.
Nonetheless, a few challenges arise when applying
both MCM/NVM methods, which leads beginners
to fail in the quantification and selection of the right
Loops and Nodes; in writing the corresponding equations;
and dealing with special case scenarios that
include Current Sources (MCM) or Isolated Voltage
Digital Object Identifier 10.1109/MCAS.2021.3092535
Date of current version: 12 August 2021
66
IEEE CIRCUITS AND SYSTEMS MAGAZINE
Sources (IVS)1 (NVM). In order to autonomously overcome
these difficulties, students may explore the advantages
of traditional circuit simulators and evaluate
their analytical/experimental results. However, while
they are paramount tools for testing, design and finetuning,
simulators simply output " measurements " , i.e.
they do not clarify the background analysis methodology
to solve the circuit-which the student is supposed
to master at the end of the course.
The improvement of quality and effectiveness in
teaching Electrical Engineering, has been a continuous
effort over the past two decades. These studies mainly
addressed the creation of computer-based tools [1]-[4],
combining technology with course content in order to
ensure a more interactive, motivating and smoother
learning experience. With the increasing interest (and
dependency) in online education, more web-based applications
emerged [5], [6] as they bring many advantages
to undergraduate students, who have anytime/
anywhere access to problems and solutions, which
dramatically improves distance-learning. Several works
have produced web-based applications to promote success
in electrical circuit analysis, providing students
with online courses [7], remote homework systems [8],
virtual laboratories for circuit simulation [9] and symbolic
analysis simulators [10], [11].
The application outlined in this paper - U=RIsolve2 -
complements the existing technologies, since most of
them have a limited range of circuits, meaning that once
the student solves the available set of exercises, and still
cannot fully understand the methods, this type of application
falls short. U=RIsolve [12], [13] is a web-based tool
that uses a circuit description model (netlist) generated
by the QUCS simulator [14] to produce a straightforward
demonstration of the analysis process. Thereby,
U=RIsolve application enables:
1In this work context, an Isolated Voltage Source is assumed as an ideal
voltage source (without internal resistance), connected in a branch
without any other components, fixing the voltage between the two
nodes delimiting that branch.
2 The application currently available at: https://www.urisolve.pt.
THIRD QUARTER 2021
https://www.urisolve.pt
IEEE Circuits and Systems Magazine - Q3 2021

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