User Defined Electrical Experiments In A Remote Laboratory

Laboratory exercises in electrical engineering courses can be performed remotely using real equipment. A number of user-defined experiments on electrical circuits have been conducted over the Internet at Blekinge Institute of Technology (BTH), Sweden; the experiments have been carried out in different locations simultaneously using the same experimental hardware located in a small closed laboratory at BTH. The laboratory provides a remotely controlled switch matrix, two function generators, a digital multi-meter, and an oscilloscope. The matrix replaces the traditional breadboard and students and other users around the globe use it to form circuits from components mounted in component holders in the matrix. It has five nodes; a jumper lead or up to four components can be connected between each pair of nodes. The laboratory supervisor or a teacher can easily swap components. Users control the instruments using virtual front panels in the same way as they had done earlier in the local laboratory; the only difference is that they no longer form the circuits and connect the test probes manually. Circuits are defined using PSpice compatible net lists. The sources and components available in the laboratory are listed in a library. This library can be added to the libraries in, for example, the evaluation version of PSpice. Students can, within certain limits, modify the circuits shown in the laboratory instruction manuals or even design circuits of their own. A virtual laboratory instructor checks the circuits formed automatically before the voltage is applied to avoid possible damage. Is it possible to establish a reasonable balance between the teachers’ needs and the complexity of the hardware? Can the virtual instructor check the circuits formed without making advanced calculations or simulations? This paper addresses these questions and discusses implementation issues.