# Virtual Instruments for Understanding DC Circuits

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Understand DC circuits, periodic waveforms, and harmonics by applying them to custom-written LabVIEW Virtual Instruments (VIs). VIs provide the hands-on experience without the expensive equipment.
This chapter is from the book

### This chapter is from the book 

This chapter's main objective is to highlight some of the commonly used definitions and fundamental concepts in electric circuits, which are supported by a set of custom-written VIs. These VIs enable students to examine various scenarios in circuits or control panels and, hence, provide an excellent tool for interactive studying. For example, a circuit can be modified easily by varying its controls on the front panel—a series resistance can be zeroed and a parallel resistance can be set to a very high value to introduce a short circuit and an open circuit, respectively. Or a dc offset can be introduced to a programmed waveform to obtain a desired average or root mean square (rms) value, which is supported by the visual display of the waveform.

This chapter is divided into five sections with accompanying custom-written VIs. The first two sections offer some basic explanations about common electrical waveforms and their distinguishing features. We then develop the concept further by studying harmonics in nonsinusoidal waveforms.

Section 2.3, DC Circuits, covers basic circuit topologies and mesh analysis. Section 2.4 presents Thevenin's and Norton's equivalent circuits. In addition, each subsection includes a set of self-study questions that are structured to assist learning and to encourage students to investigate alternative settings on the VIs.

### Educational Objectives

After completing this chapter, students should be able to

• understand the basic concepts in dc circuits, periodic waveforms, and harmonics.

• state the meaning of the terms periodic and rectified waveforms; average, rms, and maximum values; and equivalent resistance.

• solve for unknown quantities of resistance, current, voltage, and power in series, parallel, and combination circuits.

• examine the concepts of open and short circuits and describe their effects on dc circuits.

• understand Thevenin's and Norton's equivalent circuits.

• create various scenarios with the provided circuits, and verify the results analytically.

• gain skills in virtual instrumentation to create more complex and alternative systems by analyzing the programming block diagrams.

View the entire sample chapter in PDF format.