In the past these electromechanical timers were often combined with electrical relays to create electro-mechanical controllers.

Then in 1835 Joseph Henry invented the critical electrical relay, by which a weak current could operate a powerful local electromagnet over very long distances.

Mr. Hofmann said the only remaining damage to the subway system involved electrical relays that would have to be replaced.

It used electrical relays as logic switches and for storage.

The generated pulses of the local loop current operated electrical relays in these electromechanical switching systems at the central offices.

Aside from movable parts, electrical relays are also used.

While the hydraulics are not often a cause for trouble, the electrical relays are known to fail.

We're patching in to each other through old equipment-you can practically hear electrical relays opening and closing.

It is common for the ants to swarm on electrical relay switches inside air-conditioning units, until their charred bodies cause a short circuit.

The boxes containing the electrical relays that control signals were specially locked to prevent tampering.