Гиратор: Необратимый двухпортовый элемент сети

Two port non reciprocal network element
A gyrator is a passive, linear, lossless, two port electrical network element proposed in 1948 by Bernard D. H. Tellegen as a hypothetical fifth linear element after the resistor, capacitor, inductor and ideal transformer.

Tellegen named the element gyrator as a blend of gyroscope and the common device suffix tor (as in resistor, capacitor, transistor etc.) The tor ending is even more suggestive in Tellegen's native Dutch, where the related element transformer is called transformator. The gyrator is related to the gyroscope by an analogy in its behaviour. The analogy with the gyroscope is due to the relationship between the torque and angular velocity of the gyroscope on the two axes of rotation. A torque on one axis will produce a proportional change in angular velocity on the other axis and conversely. A mechanical–electrical analogy of the gyroscope making torque and angular velocity the analogs of voltage and current results in the electrical gyrator.

An ideal gyrator is similar to an ideal transformer in being a linear, lossless, passive, memoryless two port device. However, whereas a transformer couples the voltage on port 1 to the voltage on port 2, and the current on port 1 to the current on port 2, the gyrator cross couples voltage to current and current to voltage. Cascading two gyrators achieves a voltage to voltage coupling identical to that of an ideal transformer. However the gyrator can be used in a floating configuration with another gyrator so long as the floating "grounds" are tied together. This allows for a floating gyrator, but the inductance simulated across the input terminals of the gyrator pair must be cut in half for each gyrator to ensure that the desired inductance is met (the impedance of inductors in series adds together). This is not typically done as it requires even more components than in a standard configuration and the resulting inductance is a result of two simulated inductors, each with half of the desired inductance.

In microwave circuits, impedance inversion can be achieved using a quarter wave impedance transformer instead of a gyrator. The quarter wave transformer is a passive device and is far simpler to build than a gyrator. Unlike the gyrator, the transformer is a reciprocal component. The transformer is an example of a distributed element circuit.

Analogs of the gyrator exist in other energy domains. The analogy with the mechanical gyroscope has already been pointed out in the name section. Also, when systems involving multiple energy domains are being analysed as a unified system through analogies, such as mechanical electrical analogies, the transducers between domains are considered either transformers or gyrators depending on which variables they are translating. Electromagnetic transducers translate current into force and velocity into voltage. In the impedance analogy however, force is the analog of voltage and velocity is the analog of current, thus electromagnetic transducers are gyrators in this analogy. On the other hand, piezoelectric transducers are transformers (in the same analogy). Thus another possible way to make an electrical passive gyrator is to use transducers to translate into the mechanical domain and back again, much as is done with mechanical filters. Such a gyrator can be made with a single mechanical element by using a multiferroic material using its magnetoelectric effect. For instance, a current carrying coil wound around a multiferroic material will cause vibration through the multiferroic's magnetostrictive property. This vibration will induce a voltage between electrodes embedded in the material through the multiferroic's piezoelectric property. The overall effect is to translate a current into a voltage resulting in gyrator action.