Design and Implementation of Difference and Instrumentation Amplifier's Laboratory System for Education in Analog Electronics

Abstract

Difference and instrumentation amplifiers laboratory system has been designed and implemented for analog electronic education. The laboratory system contains two amplifier circuits and some auxiliary functional blocks that are constructed using discrete passive components. Objects of study with the system are the dc and ac behavior of the difference and instrumentation amplifiers, employing general purpose monolithic operational amplifiers (op-amps) as active building blocks. In particular, for development of the system on separate printed circuit board single-op-amp difference amplifier and basic three-op-amp instrumentation amplifier circuits with variable gain are implemented. Also, an unbalanced passive H bridge with the possibility of changing the differential output voltage is implemented, which allows the students to investigate the operation of the amplifiers at input signal with differential and common-mode components. To apply an external offset voltage $\mathrm{V}_{\mathrm{REF}}$ , a reference voltage source in the circuit boards is included, which is connecting to the reference terminal (REF) of the amplifiers. The implemented laboratory system is intended for analog electronic education with second-year students on the Bachelor degree programs of “Electronics” and “Automotive electronics” at the Technical University of Sofia.