1 is that they differ in function and performance. The
2 74ls02 is a four-input and gate chip that has four inputs and one output, which is high level when all inputs are high level, and low level otherwise.
And 00 is a dual-two input and non-gate chip, it has two inputs and one output, when both inputs are low, the output is high, otherwise the output is low.
3 also lies in their packaging and working voltage and other aspects, the specific use needs to be selected according to actual needs.