One of the most common Boolean or binary logic functions, OR says if there is a gate on (or “high”) signal at any of the inputs (i.e. input 1 or input 2 or input 3, etc.), to output a gate on signal. A NOR function has an inverted output: it would only be on (high) if all inputs were low (not input 1 nor input 2 are high). An XOR (Exclusive OR) would only output a high signal if one of the inputs was high, but not if both inputs were high (or low). Finally, an XNOR is the invert of an XOR function.
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OR logic