Transistor AND gate
Reminder... an AND gate is a logic circuit which has two or more input terminals and generates an 1 output only when all the inputs are 1: any other combinations outputs 0.
In this project, we're going to make a transistor AND circuit and find out how it works by referring to the schematic. Remember that input signals are 1 when key is pressed and 0 when key is released.
The output signal is 1 when the LED lights up, and 0 when the LED goes out.
Wire the project, switch power ON, and see what happens to the LED when you changes the input condition. Again, we believe no other explanation is necessary.