Since the decision condition for the setting is S=0, the S terminal is called the set 1 terminal. When S=0, R=1, the flip-flop is set to 1. When Q=1 and Q' =0, the flip-flop is set to in 1, otherwise, the flip-flop is set to 0. Generally, and the state of the terminal Q is defined as the state of the flip-flop. When two input terminals of the flip-flop are added with different logic levels, its two output terminals Q and Q' have two complementary stable states. (2) When R=0, S=1, then Q=1, Q' =0, and the flip-flop is set to 0. (1) When R=1, S=0, then Q=0, Q' =1, and the flip-flop is set to 1. The logic equation of the basic RS flip-flop is:Īccording to the two formulas, the relationship between its four inputs and outputs is: It has two input terminals R and S and two output terminals Q and Q'įigure 1.Basic RS flip-flop Simple Circuits Diagrams Consist of 2 NAND Gates The logic circuit is shown in the Figure below. Circuit StructureĬonnect the input and output ends of the two NAND gates G1 and G2 to form a basic RS flip-flop. Common chip models of NOR gates are: 74LS02, etc.ĪND-OR-NOT Truth Table II RS Flip-flop 1. When the input terminals A and B are both 0, Y will be 1. Common chip models of NAND gates are: 74LS00, 74LS03, 74S31, 74LS132, etc.Īs long as one of the input terminals A and B is 1, the output terminal Y is 0. That is, only when all input terminals A and B are 1, the output terminal Y is 0, otherwise, Y is 1. Common chip models of NOT gates are: 74LS04, 74LS05, 74LS06, 74LS14, etc. The output terminal is always opposite to the input terminal. Common chip models of OR gates are: 74LS32, etc. When one of the input terminals A and B is 1, the output terminal Y is 1 when the input terminals A and B are both 0, Y will be 0. Common chip models of AND gates are: 74LS08, 74LS09, etc. Only when the input terminals A and B are both 1, the output terminal Y is 1, otherwise, Y is 0. (Logic 1 represents high level logic 0 represents low level) The gate implementing AND operation is AND gate, that implementing OR operation is OR gate, and that implementing NOT operation is NOT gate, also called inverter gate, etc. Electronic circuits that implement basic and common logic operations are called logic gate circuits.

Cmos transistor