The oscilloscope probe is mainly used to guide the measured voltage signal from the measuring point into the oscilloscope for measurement. Probe is crucial to the accuracy and correctness of the measurement results, as it's the electronic component connecting the measured circuit and the input of the oscilloscope. The simplest probe is a wire that connects the measured circuit and the input of the oscilloscope, a complex probe consists of resistor-capacitor unit and active devices. A simple probe has no shielding measures, so it's susceptible to external electromagnetic interference. Meanwhile, larger equivalent capacitance in it would increase the load on the measured circuit, thus leading to distortion of the measured signal.