"220V Cooling Fan" rapid development of microelectronics technology, computer technology, modern communications technology, photonics technology and space technology, relay technology made new demands, the development of new technology and new technology to the development of relay technology will undoubtedly play facilitating role. "220V Cooling Fan" the rapid development of microelectronics and VLSI IC's for relays also made new demands. The first is the miniaturization and flaking. The IC package of military TO-5 (8.5 × 8.5 × 7.0mm) relays, it has high vibration resistance, can make the device more reliable; second combination and multi-functional, compatible with the IC, can be built amplifier requires sensitivity increased to microwatt level; the third is full of solids. "220V Cooling Fan" solid state relays high sensitivity, anti-electromagnetic interference and radio frequency interference.