ELECTRIC METER WITH THREE POSITION CONTROL Russian patent published in 1997 - IPC

FIELD: instruments. SUBSTANCE: device has reference power supplies 1 and 2, first and second comparators 3 and 4, indicator selection unit 5, indicator 6 with control unit 7, first and second AND gates 10 and 11, first and second OR gates 14 and 15. In addition device has third and fourth AND gates 12 and 13, two NOT gates 8 and 9, two control inputs 24 and 25. Control input 24 is connected to second input of first AND gate 10, first input of third AND gate 12 and through first NOT gate 8 to first input of fourth AND gate 13. Second control input 25 is connected to first input of second AND gate 11, second input of fourth AND gate 13 and through second NOT gate 9 to another input of first AND gate 10. Direct input of first comparator 3 is connected to another input of second AND gate 11. Direct output of second comparator is connected to another input of fourth AND gate 13. Inverting input of second comparator 4 is connected to another input of third AND gate 11. Outputs of third and fourth AND gates are connected to corresponding inputs of second OR gate 15, which output is connected to third input 19 of control unit 7. EFFECT: increased functional capabilities. 2 cl, 1 dwg, 1 tbl