1. The power supply socket of the oscilloscope must be a tripod socket, and it must be grounded reliably. In the absence of grounding wire, the power supply plug of the oscilloscope should pay attention to dividing the zero line and the fire line when it is connected, and the probe grounding wire of the oscilloscope should not be charged at one end.
Two, when testing the signal on the line, it is necessary to connect the ground wire probe before measuring the information. Because without first addressing, the probe may be electrified and damage the test element.