Positive/negative floating resistor using OTAs

A method for realizing a floating resistor based on operational transconductance amplifiers (OTAs) is presented in this paper. The proposed design is composed of only OTAs without any external resistor. The magnitude of the obtained resistance is electronically varied by adjusting the external bias currents of OTAs. Both a positive and a negative resistance can be achieved in the same circuit. The proposed scheme provides the simple configuration and low cost. The circuit performances based on the use of the commercially available OTAs are confirmed by the experimental results.