A resonator comprising: an inductor ; a capacitor ; and a switch configured to maintain energy in at least one of the inductor and the capacitor for a select period of time and to enable variability of energy in the at least one of the inductor and the capacitor for another period of time, to set a resonating frequency of the inductor and the capacitor , the select period of time or the another period of time being an operating time extent of the switch ; the resonator characterized in further comprising a controller configured to control the operating time extent of the switch to set the resonating frequency based on energy characteristics of the at least one of the inductor and the capacitor , wherein the controller is further configured to control the operating time extent of the switch based on a value associated with the inductor or capacitor , respectively by repeatedly sensing a current of the inductor or sensing a voltage of the capacitor , respectively, such that the operating time extent of the switch is controlled based on a magnitude of the sensed current or voltage respectively, and wherein the controller is configured so that it repeatedly senses the current of the inductor or senses the voltage of the capacitor , respectively, while changing the operating time extent of the switch from a minimum operating time extent to a maximum operating time extent, and configured to control operation of the switch , to set the resonating frequency, based on a determined operating time extent for the switch that has been selectively updated based on whether the then latest sensed current magnitude or latest sensed voltage magnitude, respectively, was greater than the previous largest sensed current magnitude or previous largest sensed voltage magnitude, respectively, so that the determined operating time extent corresponds to a maximum magnitude among the sensed current magnitude or voltage magnitude, respectively. an inductor ; a capacitor ; and a switch configured to maintain energy in at least one of the inductor and the capacitor for a select period of time and to enable variability of energy in the at least one of the inductor and the capacitor for another period of time, to set a resonating frequency of the inductor and the capacitor , the select period of time or the another period of time being an operating time extent of the switch ; the resonator characterized in further comprising a controller configured to control the operating time extent of the switch to set the resonating frequency based on energy characteristics of the at least one of the inductor and the capacitor , wherein the controller is further configured to control the operating time extent of the switch based on a value associated with the inductor or capacitor , respectively by repeatedly sensing a current of the inductor or sensing a voltage of the capacitor , respectively, such that the operating time extent of the switch is controlled based on a magnitude of the sensed current or voltage respectively, and wherein the controller is configured so that it repeatedly senses the current of the inductor or senses the voltage of the capacitor , respectively, while changing the operating time extent of the switch from a minimum operating time extent to a maximum operating time extent, and configured to control operation of the switch , to set the resonating frequency, based on a determined operating time extent for the switch that has been selectively updated based on whether the then latest sensed current magnitude or latest sensed voltage magnitude, respectively, was greater than the previous largest sensed current magnitude or previous largest sensed voltage magnitude, respectively, so that the determined operating time extent corresponds to a maximum magnitude among the sensed current magnitude or voltage magnitude, respectively. <EOS>