the easiest way to make an xnor gate is with a 7486 (or equivalent) integrated circuit, a quad xor gate. connect the output of one gate to one in put of another gate. connect the other input of the second gate to Vcc. the second xor gate will then act as an inverter.
7404
74ls00 is the ic no. Of nand gate
It is IC for logic AND gate.
nad gate
7404
For two input AND gate it is 7408for three input AND gate it is 7411
IC 7432 is an "OR GATE"
strobe is enable input in a digital IC...if its made active high...it will be enabled..some IC strobe is active low.. Its function is to enable the operation of the IC..or gate or Mux...
if you want to use 8*3 encoder than you must the design the circuit according to variable and with the help of k-map and you can not construct the circuit of 8*3 encoder using 7432 (which is or gate ic) only. you need AND gate 7408 and may be NOT 7404 gate according to design.
Not all the IC's are starts from 74 , it is TTL series IC's starting numbers basically 74 series are digital IC's . GATE FLIP-FLOP COUNTER REGISTER ADDER ALU
The 7400, and its variations, is a quad two input NAND gate.
The 7432 is a quad two input OR gate with TTL levels.