I am currently having problem understanding the basic circuitry of AND gate using diodes and how it works. As we know, the basic AND gate circuitry using two diodes is something like this.
And we know, that when we connect both diodes to GND (logic 0) , the current flows from Vcc to the two diodes as both are forward biased , and there will be no current passing through the output terminal because all of the current is flown through the diodes for the greater potential difference. If we connect any one of the two diodes to Vcc(logical 1) then there will be no potential difference between the diode connected to Vcc and the main Vcc, so the current will flow through the other diode and again no output current will be got. and if we connect both of them to Vcc(logical 1) then no current will pass from both diodes , hence we will get a current flow(logical 1) in the output pin. (If i am mistaken in this part then please correct) now, if we connect an LED with the output pin and connect the cathode pin is connected to GND. Just like this following schematic.
here comes my question. When both of the input diodes are connected to GND, there is a flow of current through the two diodes but why not through the LED? because the LED is connected to GND as well. Also when any one of the input diode is in logic 1 state(01 and 10 combination) , then also current can flow through the LED because the LED is also connected to GND , hence there is a potential difference between the Vcc and the cathode of LED. Why is it that only when the two input pins are in logical 1 state , only then the LED will light up?
For a more generalized way, if I use a diode instead of the LED in the output , what will happen?
If there is any problem understanding my question then I sincerely apologize. Thanks