74LS00 2 input NAND Gate WORKING
The IC has four NAND gates; however, each NAND gate has two different types of internal structures. CMOS is the first, and PMOS is the second. When we observe the structure, it may appear to be changed, yet its primary function remains the same. Four transistors make up the CMOS NAND gate. The circuit is made up of transistors and a power source, and it produces the HIGH and LOW states depending on the input combinations. The NAND gate's internal construction is shown below.

74LS00 Circuit
Q1 and Q2 will both be turned off. As a result, the total supply voltage is seen across transistors Q1 and Q2. Y1 will be HIGH because output Y1 is nothing but voltage across transistors Q1 and Q2.
When one of the inputs is HIGH, only the transistor closest to it will turn on, leaving the other off. The whole supply voltage appears across the transistor, which is in the OFF state, as a result of this. Y1 will be HIGH because output Y1 is the voltage across both transistors Q1 and Q2.
Both transistors will be ON when both inputs are HIGH, and the voltage across both of them will be zero.
Y1 will be LOW because output Y1 is the voltage across both transistors Q1 and Q2.
Examples with 74LS00 NAND Gate IC

74LS00 Circuit
Two inputs are connected to two buttons, while the output is connected to an LED. The ON and OFF states of this LED reveal the gate's output logic.
Both buttons are open and not pressed under usual conditions. Both of the gate's inputs will be LOW as a result. According to the truth table stated above, when both inputs are LOW, the output will be HIGH. The LED will light on since the output is high.
If one of the buttons is pressed. One of the inputs will be LOW, while the other will be HIGH. According to the truth table, the output will still be HIGH in this situation. The LED will light on since the output is high.
Only when both buttons are pressed will we get a LOW output, which will turn off the LED.
We discovered the truth table for chip NAND gate using these three scenarios. We can satisfy our needs by using all four gates in this manner.