Stand-by power system

摘要

Main power (e.g. an alternating voltage) is applied to a data processing system through a switch in a first state of the switch operation. The switch may have an arm movable to a first terminal to obtain the first state of switch operation and to a second terminal to obtain a second state of switch operation. A microprocessor periodically checks to determine if the main power to the data processing system has been interrupted. Upon such an interruption, the microprocessor produces a signal which causes the switch to be transferred to the second state of operation. The microprocessor is also operative to cause an alternating voltage to be produced during the interruption in the application of the main power to the data processing system. This alternating voltage is introduced to the data processing system in the second state of operation of the switch to energize the data processing system. During the transition of the switch between the first and second states of operation, the microprocessor is also operative to by-pass the switch so as to obtain the introduction of the alternating voltage directly to the data processing system. The switch may be by-passed by energizing an electrooptical coupler from the microprocessor and by energizing a triac from the voltage produced when the electrooptical coupler is energized.