Gyrator Circuit Makes DC Supply Invisible For AC Testing

摘要

Designers have long USed the gyrator circuit to create a virtual inductor employing readily available capacitors. The circuit can achieve high inductance values with relatively low capacitance values, making it easy to implement, less bulky per unit inductance, and more cost effective than physical inductors.rnThis idea shows how a gyrator can also be used to permit certain ac tests on a unit under test (UUT) that requires a dc current feed. Typical examples include devices that connect to the telephone line such as modems, fax machines, and Voice over Internet Protocol (VoIP) equipment. These devices require a current feed that will not disturb the ac termination impedance.