Need help with the probe or led...

hi guys I'm new to the circuit and I need your help..

ok here the sample question:
" as part of smart tunnel function monitoring system, a circuit is required to indicate the status of the tunnel valve. A green LED display turn on if all three valves are open. A red LED display turns on if any of the valves fail to open. When the tunnel valve isopen, its sensors produce a LOW voltage. When the tunnel valve is close, its sensor produces a HIGH voltage. Implement a logic gate circuit to meet this requirment."

*I've make the red led with nand gate, but my problem is LED should turn on if it HIGH right?. the ques say "When the tunnel valve is open, its sensors produce a LOW voltage" that mean green led should turn on if all gate open then produce LOW, but how to make led turn on if it LOW...

Regards

Depends upon how you connect the LED.

If you connect the LED between the output and ground, it will light when the output is high.

If you connect the LED between the output and the supply voltage, it will light when the output is low.

Depends upon how you connect the LED.

If you connect the LED between the output and ground, it will light when the output is high.

If you connect the LED between the output and the supply voltage, it will light when the output is low.

crutschow said:

Depends upon how you connect the LED.

If you connect the LED between the output and ground, it will light when the output is high.

If you connect the LED between the output and the supply voltage, it will light when the output is low.

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I've tried but it not works..can u provide some example..thank for response..