By inserting a large resistor in series with the probe and providing good electrical insulation, it is possible to create a probe that allows an ordinary voltmeter to measure very high voltages (up to about 50 kV). The value of the resistor must be chosen to form an appropriate voltage divider with the input resistance of the voltmeter. Because of the very high value of the resistor needed (several megohms), high voltage probes are mainly used for measuring DC and low frequency AC; the RC circuit that is formed with the parasitic capacitance of the voltmeter input will attenuate higher frequencies. http://en.wikipedia.org/wiki/Test_probe#High_voltage_probes
The P5200 can be used with any oscilloscope and enables users to safely make measurements of floating circuits with their oscilloscope grounded. The P5200 Active Differential Probe converts floating signals to low-voltage ground-referenced signals that can be displayed safely and easily on any ground-referenced oscilloscope.
WARNING: For safe operation, do not use the P5200 High-voltage Differential Probe with oscilloscopes that have floating inputs (isolated inputs), such as the Tektronix TPS2000 Series oscilloscopes and THS700 Series oscilloscopes. The P5200 High-voltage Differential Probe requires an oscilloscope or other measurement instrument with grounded inputs.
