A tuning fork apparatus (10) is vibrated via a coil (18) which encloses at least a portion of both tines (14, 16), thereby inducing mutually repulsive magnetic fields in the tines (14, 16). The coil may be elliptical in shape to reduce the size of the apparatus (10). A ferromagnetic housing may be located outside the coil (18) to form closed magnetic circuits with the tines (14, 16), to increase their magnetic repulsion. The tines (14, 16) can have different masses, such that the more massive tine is substantially undeflected. Applications include optical fibre scanning in endoscopes and microscopes.