'A device in which one circuit controls another, Marconi won the race to design one, seen <a href="http://www.j-archive.com/media/2006-05-18_J_28.jpg" target="_blank">here</a>, for the telegraph'
a relay
MACHINERY: A device in which one circuit controls another, Marconi won the race to design one, seen here, for the telegraph
A device in which one circuit controls another, Marconi won the race to design one, seen here, for the telegraph
A device in which one circuit controls another, Marconi won the race to design one, seen here, for the telegraph
MACHINERY
a relay
MACHINERY