# SR Flip-flop logic I am trying to understand SR flip-flops from a book which uses the above circuit to describe different states that this circuit can get in. Initially, both the switches are open and the current flows from the output of left NOR gate( highlighted in red in the image). However, I am struggling to understand as to why both the inputs to the left NOR gate are zero and the right NOR gate aren't since their inputs are dependent on each other's output. In other words, why can't we assume that since in the beginning we have no input voltages to right NOR gate the output should be 1 which will mean that the current will be between the wire connecting output of the right NOR and the input of the left NOR?

• i think that the book author is assuming that an incandescent bulb is being used ... the filament resistance is very low when cold ... at powerup, that would pull the output of the right gate low for a brief moment, just long enough for the left gate to supply a high to the right gate input Jul 12, 2020 at 16:50