June 14, 2015
June 14, 2015
June 17, 2015
Division Experimentation & Lab-Oriented Studies
26.348.1 - 26.348.15
Chua’s Circuit for Experimenters Using Readily Available Parts from a Hobby Electronics StoreThe Chua’s circuit was first developed in 1983 and is renowned for being the chaotic circuit thatis most simple to construct. Several books and articles have been written on constructing Chua’scircuits in several variations. The circuit is “simple” to construct, provided that all the necessarycomponents are readily available along with all the measuring tools required to observe thechaotic attractor. The traditional Chua’s circuit consists of three energy storing electricalcomponents, specifically two capacitors and one inductor. Numerous papers have consideredalternative designs of Chua’s circuit to eliminate the inductor. Some reasons for this include: i) The changing state to be measured for an inductor is the current passing through it, which is difficult to measure accurately. ii) The inductance value required to build the circuit may not be readily available. iii) Often, the parasitic resistance of the inductor can be large to prevent the Chua’s circuit to not function as intended.A common technique is to replace the inductor with an inductor-gyrator circuit. Although Chua’scircuit can be built readily by using available components, the observations of the attractor andthe nonlinear phenomena of bifurcation are commonly done by using an oscilloscope, which cancost few hundred to couple of thousand dollars. An alternative inexpensive solution is to use the“Line-In” port of a desktop sound card, which can provide two analog input signals with asampling rate of 44 kHz or more.The recommended procedure to build a Chua’s circuit using readily available resources waspublished in 1990s. Currently, these prior solutions are not directly applicable for the commonhobbyist. Over the past three decades many hobby electronics stores, where one may haveacquired all necessary components to build a Chua’s circuit (except the inductor), are no longerin business in the United States. Franchises such as RadioShack and Fry’s Electronics are theonly locations where one may acquire electronic components (other than from online vendors)but their selection is very limited. Their stock for hobby electronics is currently geared to supportprogrammable development platforms (e.g., Arduino and Raspberry Pi) instead of analogelectronics. Moreover, the measurement of analog signals using a Line-In port of a desktopsound card is no longer a relevant solution to replace an oscilloscope. The 1990’s desktops camecommonly equipped with a sound card which included a Line-In port. Current computer marketis split between desktop and laptop computers, and almost all laptops do not have a Line-In port.This paper will present a Chua’s circuit that can be constructed entirely out of RadioShackcomponents, and show that an external USB audio sound card can be used as an inexpensivereplacement to an oscilloscope and a desktop sound card. This solution allows the commonhobbyist, curious student, or educator to build a chaotic circuit in a short period of time. Thiswork can make chaotic systems more accessible and easily integrated in student projects orclassroom demonstrations. Courses in which students may benefit from a live demonstration of achaotic circuit include circuit theory, electronics, nonlinear dynamics and chaos, nonlineardifferential equations, applied nonlinear control theory, dynamic system modeling, and others indepartments such as electrical engineering, mechanical engineering, physics, and mathematics.
Siderskiy, V., & Mohammed, A. A., & Kapila, V. (2015, June), Chua’s Circuit for Experimenters Using Readily Available Parts from a Hobby Electronics Store Paper presented at 2015 ASEE Annual Conference & Exposition, Seattle, Washington. 10.18260/p.23687
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