Abstract: An apparatus to introduce impact pulses into the human body has an impact transmitter (8) displaceable in an axial direction and an electromagnetic impact generator (2, 6; 26, 24; 36, 34) driven by current pulses and supplying force impulses to the impact transmitter. The impact generator includes a magnet fixed in position and having a magnetic field, and a coil (6, 26, 36) displaceable in the direction of transmitter displacement in the field of the magnet (2; 23, 24; 33, 34), the coil being energized by the current pulses to be axially displaced and drive the impact transmitter (8).

Abstract: A mechanically operating pendulum clock is provided with an electronic cocting device which comprises a quartz oscillator. An electronic frequency divider generates from the oscillation frequency of the quartz oscillator a frequency equal to that of the pendulum. A permanent magnet is arranged on the pendulum to cooperate with a control coil forming an electro-mechanical converter. The control coil is effective at least in the two turning positions of the pendulum. A contact-free pendulum sensor is also provided. A proportional electronic control device includes a converter which produces rectangular signals from the signals emitted by the quartz oscillator and the sensor, and a comparator is adapted, depending upon the reciprocal phase position of the quartz oscillator and sensor signals to transmit delay or acceleration signals to the control coil as well as opposing acceleration or delay signals to the control coil but phase-shifted by 180.degree..