Influence of the positive feedback resistor resistance on the amplitude-frequency response of the gyrator based on the operational amplifier
DOI:
https://doi.org/10.17721/1812-5409.2026/1.36Keywords:
gyrator, feedback, operational amplifier, active filter, amplitude-frequency responseAbstract
You can get rid of the use of inductors in active RLC filters of the second and higher orders by using a gyrator – an RC cell included in the positive feedback circuit of an operational amplifier. This "active inductor" circuit allows you to implement active filters even using microelectronics devices. The purpose of our work is to develop practical recommendations for choosing the value of the feedback resistor resistance in gyrator circuits and to investigate its influence on the amplitude-frequency characteristic of the device.
As a research method, computer modeling was used in the LTSpice software application, during which the main characteristics of the oscillatory LC circuit and the circuit with a gyrator on an LT1006 operational amplifier were compared, and the corresponding amplitude- and phase-frequency characteristics were obtained.
It is shown that the position of a maximum of amplitude-frequency response of the circuit with a gyrator is closer to the resonant frequency of the RLC oscillating circuit, when the resistance value of the coupling resistor is closest to the output resistance of the operational amplifier, but at the same time it must be at least 100 Ohm. To ensure a stable transmission coefficient of the circuit with a gyrator when the resonant frequency changes tenfold, the resistance must be about half the operational amplifier's output resistance, 300 Ω in this case.
Pages of the article in the issue: 280 - 284
Language of the article: English
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