Switching on and off controlling circuit for sales process e.g. shop balance, processing device, has interlocking device selectively permitting or preventing transmission of switching signal from switch to digital signal latch

摘要

The circuit has a power supply unit (N) with an auxiliary supply comprising a set of discrete elements. A set and reset digital signal latch (IC1) i.e. flip-flop, has an output (Q) for controlling the power supply unit, and a switch i.e. push button (TA1) connected with the digital signal latch. An interlocking device comprising inverted Schmitt-triggers (IC3, IC4) and collector resistor (R2), is controlled by a processor (CPU). The interlocking device selectively permits or prevents transmission of a switching signal from the switch to the signal latch.