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ERIC Number: EJ1250878
Record Type: Journal
Publication Date: 2020-Apr
Pages: 5
Abstractor: As Provided
ISSN: ISSN-0021-9584
Low-Cost, High-Performance Lock-In Amplifier for Pedagogical and Practical Applications
Xu, Xicheng; Suganuma, Yoshinori; Dhirani, Al-Amin
Journal of Chemical Education, v97 n4 p1167-1171 Apr 2020
Lock-in amplifiers (LIAs) are commonly used in chemistry laboratories to improve noise-to-signal ratios. Constructing and testing a suitably designed LIA provide undergraduate students with an excellent opportunity to learn about theory, construction, and applications of LIA. In particular, students can learn about time-dependent behavior and various components, from resistors (R) and capacitors (C) to packaged microchips such as demodulators and phase shifters. We provide here design and performance characteristics of a two- (Vx, Vy) channel LIA based on balanced modulator/demodulators (AD630). The LIA includes configurable resistor-capacitor (RC) high-pass and low-pass filters, various op-amp circuits, and a phase-shifter. Various configurations of resistors/capacitors, as well as salt solutions and isopropanol/pentane mixtures, are used as samples to measure conductance or capacitance to test both V[subscript x] and V[subscript y] channels of the LIA. The results are consistent with behaviors expected theoretically. The LIAs yield excellent noise/signal ratios with peak-to-peak values that are <0.2% and that compare favorably with commercial LIA performance.
Division of Chemical Education, Inc. and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A