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In this circuit I try to toggle a LED on and off when a switch is pressed.

Given the nature of the T flip-flop, when the switch is triggered, it toggles the clock and since T=1 always, it essentially reverses the state of Q, so in other words, it toggles the LED on and off.

OK, the LED has its connection to the power supply, that means it has to connect to GND in order to toggle ON.

Now what does this mean? When the TFF output is 1, the LED will turn ON? Or OFF? When TFF output is 0, the LED is OFF? Or maybe a 0 potential is like Ground, that means when TFF Q=0, the LED is ON?


1 Answer 1


When Q is high the potential difference between Vcc and Q its small, so the LED is off. When Q is low, the potential difference between Vcc and Q is higher, so the LED switches on.


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