An electrical relay using conducting liquid in the switching mechanism. The
relay is amenable to manufacture by micro-machining techniques. In the
relay, two electrical contacts are held a small distance apart. The facing
surfaces of the contacts each support a droplet of a conducting liquid,
such as a liquid metal. An actuator is energized to reduce the gap between
the electrical contacts, causing the two liquid metal droplets to coalesce
and form an electrical circuit. The actuator is then de-energized and the
electrical contacts return to their starting positions. The liquid metal
droplets remain coalesced because of surface tension. The electrical
circuit is broken by energizing an actuator to increase the gap between
the electrical contacts and break the surface tension bond between the
liquid metal droplets. The droplets remain separated when the
piezoelectric actuator is de-energized because there is insufficient
liquid metal to bridge the gap between the contacts. Additional conductors
are included in the assembly to provide a coaxial structure and allow for
high frequency switching.