A 2-input gate that can be used to pass a digital waveform unchanged at certain times and inverted at other times is ___________

The 2-input gate that can be used to pass a digital waveform unchanged at certain times and inverted at other times is the XOR (exclusive OR) gate. An XOR gate has two input signals and one output signal. The output is HIGH (1) if the two input signals are different, and LOW (0) if the two input signals are the same. In other words, an XOR gate produces an output signal that is the "exclusive or" of its two input signals. When one of the input signals is held at a constant logic level (either HIGH or LOW), the XOR gate can be used to pass the other input signal unchanged or inverted, depending on the value of the constant signal. If the constant signal is HIGH, the output signal will be inverted; if the constant signal is LOW, the output signal will be unchanged. This property of the XOR gate makes it useful in digital electronics for a variety of applications, such as data encryption, error detection and correction, and clock synchronization.