Negative edge triggered flip flop 6 nor gates

The flip-flop goes to an unstable state as both the output goes LOW. When the input state R = 0 and S = 0 is an invalid condition and must be avoided because this will give both outputs Q and З¬ at logic level вЂњ1вЂќ at the same time and the necessary condition is that Q to be the inverse of З¬. The truth table of the Set/Reset is given below: StateДЇrom the truth table, it is clear that when both the inputs S = 1 and R =1 the outputs Q, and З¬ can be at either logic level вЂ1вЂ™ or вЂњ0вЂќ depending upon the state of the inputs. Therefore, the flip-flop circuits вЂњRESETвЂќ state has been latched. If the set input S now changes the state to logic вЂњ1вЂќ with the input R remaining at logic вЂњ1вЂќ, the output Q still remains LOW at logic level вЂњ0вЂќ. The output Q is fed to input B, so both the inputs to NAND gate Y are at logic вЂњ1вЂќ., therefore, Q = 0. As gate X has one of its inputs at a logic вЂњ0вЂќ its output Q must equal logic level вЂњ1вЂќ. In this second stable state, Q is at logic level вЂ0вЂќ and its inverse output Q is at logic level вЂњ1вЂќ. Therefore, the flip-flop circuit is said to be вЂњLATCHEDвЂќ or вЂњSETвЂќ with Q = 1 and З¬ = 0. The output at Q remains at HIGH or at logic level вЂњ1вЂќ as one of its inputs is still at logic level вЂњ0вЂќ.ДЄs a result, there is no change in state. The NAND gate Y input are now (R = 1) and (B = 0).

The reset input R changes its state, and goes HIGH to logic вЂњ1вЂќ with S constant at logic вЂњ1вЂќ. Both the inputs of the NAND gates X are at logic вЂњ1вЂќ, and therefore, its output Q must be at the logic levelвЂќ0вЂќ. The Output (Q) is fed back to the input вЂњAвЂќ. Therefore, its output Q must be at a logic level вЂњ1вЂќ (NAND gate principles). If the input R is at logic level вЂњ0вЂќ (R = 0) and input S is at the logic вЂњ1вЂќ (S = 1), the NAND gate Y has, at least, one of its inputs at a logic вЂњ0вЂќ. The two outputs are Q and Q bar as shown in the figure below:Д¬onsidering the above circuit. The device consists of two inputs one is known as SET, (S) and the other is called as RESET, (R). The feedback is fed from each output to one of the other NAND gate input. It forms Set/Reset bi-stable or an active LOW RS NAND gate latch. The symbol of the RS Flip-Flop is shown below:ДЄ pair of cross-coupled 2 unit NAND gates is the simplest way to make any basic one-bit set/reset RS Flip Flop. The RS Flip Flop actually has three inputs, SET, RESET and its current output Q relating to its current state. The basic NAND gate RS Flip Flop circuit is used to store the data and thus provides feedback from both of its outputs again back to its inputs.

Flip flop word means that it can be вЂњFLIPPEDвЂќ into one logic state or вЂњFLOPPEDвЂќ back into another. It depends upon the set/reset condition of the flip-flop. The flip-flop is reset back to its original state with the help of RESET input and the output is Q that will be either at logic level вЂњ1вЂќ or logicвЂќ0вЂќ. It has two inputs, one is called вЂњSETвЂќ which will set the device (output = 1) and is labelled S and another is known as вЂњRESETвЂќ which will reset the device (output = 0) labelled as R. The Flip Flop is a one-bit memory bi-stable device. The RS Flip Flop is considered as one of the most basic sequential logic circuits.

In this article, RS Flip Flop is explained in detail. There are two types of flip flop one is RS Flip Flop and JK Flip Flop.

Negative edge triggered flip flop 6 nor gates