This NAND gate circuit is not working as its supposed to!

[drkilljoy]

Hello, this circuit here was something I made to illustrate the NAND gate inside the 74HC00 integrated chip. For some reason, it's not following the truth table. When both switches are LOW, the light bulb turns on, which makes sense as it's supposed to do that. But when I switch one slide switch to HIGH, the light bulb turns off?? It's not supposed to do that according to the truth table for a NAND gate. The light bulb should only turn off if both inputs are HIGH, but it doesn't do that.

[ruilviana]

Reverse the LED and connect to the GND instead of + VCC,
and it will work as it should.

RV mineirin

[paulpaulson]

Hello,
you have to connect the led to ground.
Than you will have the "true" truth table

[drkilljoy]

Ohhhhhh, thank you!!!!!

[drkilljoy]

Thank you!!!!