Abstract: The motion of an electromechanical device such as a relay may be analyzed through the use of the present system. A bundle of fiber optic filaments are located with one end adjacent the movable object which is to be sensed or analyzed. This movable object may, for example, be the armature of an electromagnet. With regard to the fiber optic probe, half of the fiber optic elements may be provided with input illumination and the other half of the bundle may be connected to transmit reflected light from the moving armature to a remotely located light-sensitive element such as an opto-transistor. An oscilloscope is provided to monitor the response of the electromagnet to applied signals. An actuating circuit is connected not only to apply energizing current to the electromagnet, but also to trigger the sweep of the oscilloscope.