The ICE Corporation proposes to design and manufacture a family of power hybrid circuit dc switches, including optical-isolation, over-current and over-temperature protection and drive networks. The first step of phase ii will be to improve the switch designed and fabricated during phase i. This includes improvements in switching speeds, switching delays and reducing protection threshold variations with temperature and power supply voltage. The next step will be the design of a family of approximately five switches with a current capacity range of from 1 to 50 amperes, although exceeding 50 amperes will be investigated. An attemp to extend Phase i's 32 volt operating potential to 500 volts will be made. A major effort will be made to eliminate the current-sense resistor of phase i by using current-sensing fets. The optical-isolation, cmos and ttl compatibility of phase i will be maintained. Various harmetic packages will be investigated, including the to-204 (to-3) and to-213 (to-66). Conformance with mil-std-833b will be attempted to encourage later government purchases.