WEBVTT 00:00.000 --> 00:04.769 The experiment is repeated with masses 00:04.769 --> 00:19.560 Plan of mass installed, disruptive and victim at the same distance: the result is catastrophic! So why install a ground plane? 00:19.560 --> 00:29.301 We have doubled the amplitude of the parasite! 00:29.301 --> 00:36.259 Because a capacitance is inversely proportional to the insulator separating the conductors. Before the plan: 3.5 cm of insulation. With the plane: we replace the 3.5 cm of air with copper! 00:36.259 --> 00:47.478 It can be seen here: approaching the ground plane (not referenced) reduces the insulating distance between conductors! Reducing it to the single insulation of the wires! 00:47.478 --> 01:04.607 Indeed, it comes to the same as approaching disruptive and victim without a ground plane! 01:04.607 --> 01:25.624 Conclusion: a non-referenced mass plane: floating; is worse than nothing at all! So metallic and other troughs must be equipotential! 01:25.624 --> 01:32.955 We will connect the mass of our devices to the ground plane ... 01:32.955 --> 01:43.414 The result is spectacular, I will increase the sensitivity of the measurement ... 01:43.414 --> 01:58.657 With a braid, the envelope is similar but the spikes of high frequency are well attenuated! 01:58.657 --> 02:08.915 Let's see the difference! 02:08.915 --> 02:21.900 We will validate it even better in a video with the drive as disruptive 02:21.900 --> 02:28.903 Interesting question: I disposed disruptive and victim on the ground plane ... 02:28.903 --> 02:39.936 Question 1: while keeping the gap between disruptive and victim, I move away from the mass plan ... Better, the same or worse? 02:39.936 --> 02:50.342 We notice that it is worse: the ground plane offers a nice attenuating effect, tranquilizer! 02:50.342 --> 02:57.568 And now ? If the disturber, the 'dirty' wire from the ground plane is moved away, what about? 02:57.568 --> 03:07.430 We can assume that he will not 'dirty' the mass plane again ... 03:07.430 --> 03:13.473 Well no ! The result is worse! Nor must the disturber be removed! 03:13.473 --> 03:23.864 A mass is equipotential! The disturber will modify its value but it will remain identical at all points. No matter the value of a reference as long as it is unique! 03:23.864 --> 03:34.465 forbidding any difference in potential within it because its impedance is zero, and therefore no stray voltage induced in the wires! 03:34.465 --> 03:49.527 What counts is that the reference seen by all the electronics, including disturber and victim of measurement, is unique: equipotential 03:49.527 --> 04:02.796 The measuring instruments have an aluminum plate as a ground plane. It offers equipotentiality to the device! Same for car chassis, aircraft cabins ... 04:02.796 --> 04:18.775 In order for the ground plane to be effective, its impedance must be low and it must collect all the signals in order to prevent any induced voltage since the reference is unique! 04:18.775 --> 04:35.275 The ground plane offers a semi-shielding!