RC TIME CONSTANT MEASUREMENT

In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for characterizing a device under test. An electrical waveform is received from the device under test and sampled to generate an array of data values. User input selects a particular position of the electrical waveform on a display, and identifies a corresponding starting time. A decay of a value at the starting time is identified and the array is analyzed to identify multiple data values that correspond to the decayed value. An ending time is then determined using the multiple data values, and a decay time between the starting time and ending time is determined and presented on a display device.