Abstract: A preformed thermal fuse comprising two electrodes, first and second layers of solder, and a conductive bridge comprising a non-paste solder material is disclosed. The conductive bridge has a melting temperature which is substantially equivalent to the predetermined actuation temperature of the fuse. The melting temperatures of the first and second layers of solder are selected to allow reflow soldering of the device.

Abstract: A lightning surge resistor network includes a ceramic substrate and a thick-film resistor deposited onto the substrate. To prevent material spatter and to contain and isolate any arcing that can occur in the event the thick-film resistor opens during a severe over voltage condition, a ceramic cover is mounted over the thick-film resistor. The thick-film resistor is thus fully contained between the ceramic substrate and the ceramic cover. Preferably, the ceramic cover is adhered to the ceramic substrate by means of an adhesive film deposited onto either the cover or the substrate adjacent the outer periphery of the cover. Preferably, the mount of adhesive is reduced at preselected locations along the outer periphery of the cover to form weakened areas in the seal between the cover and the substrate. The weakened areas permit gasses to escape in a predetermined direction in the event excessive pressures are formed under the cover when the thick-film resistor opens under an over voltage condition.