In practical work, the probe system (including probe and probe connection accessories) must also be used to introduce the signal of the measured circuit into the internal digital oscilloscope, so the performance of the probe system directly determines the degree of consistency between the signal introduced into the digital oscilloscope and the measured signal.
In order to obtain effective measurement results and reproduce the measured signals truly, the following three factors are mainly considered when selecting the probe system:
Physical connections, minimal impact on circuit operation, and degree of consistency with the original signal. For the first two factors, the probe attachment should be selected correctly, and for the last factor, the bandwidth of the probe system should be selected correctly. In the whole test system, the bandwidth is determined by the lowest part of the system bandwidth, so the bandwidth of the probe system must be considered when testing the signal.At the same time, the probe system also becomes a part of the measured circuit, which has certain load effect.The load characteristics of probe system are shown in three aspects: input resistance, capacitance and inductance of probe system.An ideal probe system paired with a digital oscilloscope will minimize this load characteristic and give full play to the ability, characteristics and tolerance of the digital oscilloscope to truly reproduce the measured signal.Therefore, when choosing the probe system, it is better to choose the type of probe recommended by the manufacturer, and select the corresponding attachment according to the function.