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logiccombinationscircuit

Combinational circuit?

Here is a diagram showing the implementation of a an airplane's landing gear warning logical circuit.

I understand the output for any combination of input for each sensor however what if all inputs were low (0), meaning each of the landing gear was extended. Wouldn't the NOR gate above evaluate to (1) which represents retracted gear giving a false warning? I am pretty sure the open circles in the diagram represent the not gate unless there is something I am missing. Thanks

Solution

  • The "1" at the output of the NOR gate and the +v ("1") on the LED Anode will keep the LED off.