Inverter (logic gate)

This schematic diagram shows the arrangement of NOT gates within a standard 4049 CMOS hex inverting buffer.

The inverter is a basic building block in digital electronics. Multiplexers, decoders, state machines, and other sophisticated digital devices may use inverters.

Digital inverter quality is often measured using the voltage transfer curve (VTC), which is a plot of output vs. input voltage. From such a graph, device parameters including noise tolerance, gain, and operating logic levels can be obtained.

The tolerance to noise can be measured by comparing the minimum input to the maximum output for each region of operation (on / off).