Shmoo plot

In electrical engineering, a shmoo plot is a graphical display of the response of a component or system varying over a range of conditions and inputs. Often used to represent the results of the testing of complex electronic systems such as computers, ASICs or microprocessors. The shapes of some responses can be irregular enough to resemble Al Capp's shmoo. For example, when testing semiconductor memory, voltages and refresh rates can be varied over specified ranges. Other examples of conditions and inputs that can be varied include frequency, temperature, system- or component-specific variables, and even varying knobs tweakable during silicon chip fabrification producing parts of varying quality which are then used in the process. Often one 'knob' or variable is plotted on one axis against another knob or variable on another axis, producing a two dimensional graph. This allows the test engineer to visually observe the operating ranges of the device under test. This process of varying the conditions and inputs to the component or system may sometimes be referred to as 'shmooing' but more officially known as electrical testing or qualification.