Abstract: A tuning fork resonator has electrodes 7 and 8 on the opposite main surfaces of each tine and lateral electrodes 9 and 11 along the edges of each tine. The electrodes 7 and 8 of one tine are connected to the electrodes 9 and 11 of the other tine and to one pole of the supply. The other electrodes are similarly connected to the other pole. The electric fields extend parallel to the main surfaces of the tines. In order to improve the uniformity and density of the fields, grooves 4 and 5 are etched along one main surface of each tine and the electrode 8 has parts extending into the grooves. Various modifications are possible including omission of the part of the central electrode between the grooves, provision of a single, central longitudinally groove and the provision of opposing grooves in both main surfaces. Electrical power consumption is reduced.