The interactive graphic shows the adjustment of a probe. By clicking the probe trimmer the capacity changes. Most oscilloscopes output a test frequency of 1kHz. This frequency is applied to the probe and the measured signal is displayed on the scope.

Probe of an oscilloscope

A probe is used to define the connection between the oscilloscope and the signal to be measured. It is also possible to use a simple cable, but then the resistance and capacity of the measurement is undefined. At low frequencies in the kilohertz range, this does …

Differential probe: active ground-free probe.

The differential probe is a special form of the active probe . The differential probe measures the difference between two voltage potentials, without affecting the oscilloscope ground with the circuit under investigation. This avoids the grounding problem .

What do I need an active probe for? To answer this question one first has to look at the properties of a passive the probe. The passive probe consists of a resistor and a (trim) capacitor for balancing. The oscilloscope is composed of an input impedance of one megohm and …