page_title: Electric clock
section_title: Electromagnetic clock
hierarchical_section_title: Electric clock / Electromagnetic clock
caption_attribution_description: Français&#160;: Une des premières pendules électriques, modèle français alimenté par batterie. English: An early French electric clock, powered by a battery. This type is called an electromagnetic clock. It keeps time with a pendulum, but the pendulum receives pushes to keep it swinging by magnetic force from a solenoid electromagnet. (lower right). When the pendulum swings through its bottom position, switch contacts (center) close the circuit and a pulse of current flows through the solenoid from the battery (not shown), giving the pendulum a push.
context_page_description: An electric clock is a clock that is powered by electricity, as opposed to a mechanical clock which is powered by a hanging weight or a mainspring. The term is often applied to the electrically powered mechanical clocks that were used before quartz clocks were introduced in the 1980s. The first experimental electric clocks were constructed around 1840, but they were not widely manufactured until mains electric power became available in the 1890s. In the 1930s the synchronous electric clock replaced mechanical clocks as the most widely used type of clock.
context_section_description: The configuration of this device is comparatively very simple and reliable. The electric current powers either a pendulum or an electromechanical oscillator.
  The electromechanical oscillator component has an attached magnet that passes two inductors. When the magnet passes the first inductor or sensor, the simple amplifier causes the current through the second inductor, and the second inductor works as an electromagnet, providing an energy pulse to the moving oscillator. This oscillator is responsible for the accuracy of the clock. The electronic part would not generate electrical pulses if the oscillator was absent or did not move. The resonant frequency of the mechanical oscillator should be several times per second.
caption: Early French electromagnetic clock
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