XOR and XNOR gates

Description

A demonstration of the XOR and XNOR gates. Click the input switches to toggle the corresponding input value between 0 and 1, and watch the resulting behaviour. You can also use shift+click to toggle the input value between the states 0, 1, Z (tri-state, not driven) and X (undefined). Alternatively, type the indicated bindkeys (a,b,s,d,f,g,w,e,r,t) to control the switches.

Note that two different interpretations exist for the concept of a 'multiple-input' XOR gate. First, the 'either A or B or C or ...' interpretation means 'exactly one of the inputs is true'. The second interpretation constructs a multiple-input XOR gates from a cascade (chain/tree) of two-input XOR gates, which corresponds to the parity of the input values.

For example: The following table shows the truth-table of the different gates for three inputs:

  C B A    1-of-3   even-parity  odd-parity
  0 0 0    0        1            0
  0 0 1    1        0            1
  0 1 0    1        0            1
  0 1 1    0        1            0
  1 0 0    1        0            1
  1 0 1    0        1            0
  1 1 0    0        1            0
  1 1 1    0        0            1

For a demonstration of the parity interpretation, see the parity generator applets at and .

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