Radiofrequency medical devices for ohmic heating of tissue of a patient include a temperature sensor carried by and in thermally conductive relationship with a thermally conductive electrode. The sensor is connected for feedback to a control circuit that modulates RF power applied to the electrode according to the signal received from the temperature sensor. The control circuit and RF power supply alternate between two operating modes. In the first mode the RF power supply applies RF power to the electrode. In the second mode the control circuit senses a signal from the temperature sensor in the absence of RF signal. The control circuit compares the signal from the temperature sensor to a set value and modulates the RF power applied to the electrode in accordance with the set value.