Analogs of the gyrator exist in other energy domains. He became interested in tuners such as a gyrator and a phase-locked loop (PLL). The overall effect is to translate a current into a voltage resulting in gyrator action. Unlike the gyrator, the transformer is a reciprocal component. Numerous passive circuits exist in theory for a gyrator function. The gyrator was invented by him around 1948. From the governing equations, the instantaneous power into the gyrator is identically zero. The element is usually implemented from a generalized impedance converter (GIC) or gyrator. It is not essential, however, to have both the transformer and gyrator. Although a gyrator is characterized by its resistance value, it is a lossless component. Unlike the four conventional elements, the gyrator is non-reciprocal. The gyrator is a necessary element in analysis because it is not reciprocal. A gyrator can be used to transform a load capacitance into an inductance. Gyrator circuits are extensively used in telephony devices that connect to a POTS system. The gyrator is related to the gyroscope by an analogy in its behaviour.