Another great oscilloscope video from Alan Wolke. In this video, he addresses ground lead length and it’s effects on signal quality. He writes:
This video illustrates the effects that the scope probe’s ground lead or ground wire length can have on the integrity of the signal that you measure. The ground wire introduces unwanted inductance into the probe measurement path. This inductance will affect the high frequency content of the signals being measured. For digital signals, this most often results in overshoot and ringing associated with the rising and falling edges of the signals. The faster the rise/fall time of the signal, the more it will be affected by the probe’s ground inductance. The video goes through two signal examples, one from a signal generator, and one from an integrated 30MHz CMOS crystal oscillator. The affects of the different ground lead lengths are dramatically shown on the scope.
You can check out all his other videos here — they contain a wealth of information about how to get the most out of your equipment.