A system including first and second electric or electronic circuits galvanically isolated from each other, and a coupling device coupling the first circuit to the second circuit, the coupling device including a variable-capacitance capacitor including first and second electrodes mobile with respect to each other, separated by an insulating region, and third and fourth electrodes electrically insulated from the first and second electrodes, capable of receiving a control signal to vary, by an electrostatic, electromagnetic, or piezoelectric actuation mechanism, the relative position of the first and second electrodes, to vary the capacitance between the first and second electrodes.

A system including first and second electric or electronic circuits galvanically isolated from each other, and a coupling device coupling the first circuit to the second circuit, the coupling device including a variable-capacitance capacitor including first and second electrodes mobile with respect to each other, separated by an insulating region, and third and fourth electrodes electrically insulated from the first and second electrodes, capable of receiving a control signal to vary, by an electrostatic, electromagnetic, or piezoelectric actuation mechanism, the relative position of the first and second electrodes, to vary the capacitance between the first and second electrodes.