Switch selectively connecting auxiliary current source to computer - has Schmitt trigger tripped by manually operated switch only when main supply source voltage is available

摘要

The auxiliary (battery) current supply is for an equipment e.g. a computer memory normally supplied from a main current source. It may be selectively activated, e.g. when the computer is being moved between two operating sites, to ensure that the battery is not damaged by too great a discharge, which may be more costly than re-imputting data to the memory. A Schmitt trigger (6) can be tripped by a manually operated switch (7) only when the voltage from the main supply source (1) is available. This voltage energises a relay (10) coil (9) which connects the supply, the Schmitt trigger input and its coil (9) in parallel with the main supply source (1), and the auxiliary supply source (4) to the equipment (L).