Page 46 - Handout Digital Electronics

Note that in the AND logic gate, the output is 1 only when both inputs are 1

Activity

1 Consider the proposition: If it is raining or the weather forecast is bad then I take an umbrella. What
logic gate can you use to implement the truth table for the above proposition?

2 Produce a truth table using the input variables: RAINING, NO CAR and the output variable
UMBRELLA. The input combinations are: FALSE and TRUE, the output UMBRELLA can only be
TRUE or FALSE.
6.6 The NOR logic gate

The NOR gate is formed by connecting an INVERTER (NOT gate) at the output of an OR gate. This
gate produces complementary outputs to the OR gate for example:

Standard symbol

F = A + B

Truth Table

A B F
0 0 1
0 1 0
1 0 0
1 1 0

6.7 The NAND logic gate

The NAND logic gate is formed by connecting a NOT gate to the output of an AND gate and this gate
produce complementary outputs to the AND gate for example

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