Tek High Voltage Probes derating with frequency

[PartialDischarge]

For some time I've been curious about the derating with frequency in HV x1000 tek probes. Attached is the derating for one of the first models, P6013A, 12kV@100kHz, newer models have a similar derating. So my question is exactly what are those deratings due to:

1) Resistor Voltage gradient
2) HF dielectric loses
3) Damping resistor

I understand #1 (the size and intercapacitance of the ceramic 99.9Mohm resistor voltage limits), but not #2 and #3. And what exactly is the damping resistor? Any help?

[T3sl4co1l]

At HF, the main (100M) resistor is bypassed by compensation capacitors, putting all the voltage drop across the series resistors.

The series resistors (and the shunt resistors in the compensation box) set the HF resistance, and division ratio, independent of the LF components.

Tim

[PartialDischarge]

I wonder if they come up with graphs like these theoretically or experimentally, in the latter case I'd like to see those power HV amplifiers on ebay

[T3sl4co1l]

Well, if it were experimental, it would probably be a noisy, sparse data set, interpolated with a curve.  Instead, they present a PWL graph.  It's a Bode plot derived from the relevant limits (V and P).

Easy enough to see.  Take this one for example,





The RC circuits are simply crossovers, where the high value resistors matter at low frequency, and the low value resistors matter at high frequency.

Tim