2-17 Figure 2-16.NOR gate input and output signals. TRUTH TABLE The Truth Table for a NOR gate with K and L as inputs is shown below. K L f 0 0 1 0 1 0 1 0 0 1 1 0 f = L K + Q20.   How does a NOR gate differ from an OR gate? Q21.   What will be the output of a NOR gate when both inputs are HIGH? Q22.   What is the output Boolean expression for a NOR gate with R and T as inputs? Q23.   In what state must the inputs to a NOR gate be in order to produce a logic 1 output?   VARIATIONS OF FUNDAMENTAL GATES Now that you are familiar with fundamental logic gates, lets look at some variations of these gates that you may encounter.