A small electrical signal can control the position of a large motor using this approach.

These signals control incoming and outgoing connections as well as session parameters.

Instead, an electrical signal travels through a wire and controls the accelerator.

These electrical signals control the heart rate and rhythm.

A main signal controls a train movement along a running line.

Similarly, he said, "signals out of the brain control the arm, but there are also sensors in the muscles and skin that send information back, too."

On the left, the signal controls the track to the left of the signal.

On the right, the signal controls the track to its right (no arrow, round plates).

A further signal with a side arm controlled entry to the 'yard' and the road crossing beyond.

A color television system is identical except that an additional signal known as chrominance controls the color of the spot.