Re: HV Oscilloscope probe (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 01 Sep 2007 07:26:52 +0200
From: Herwig Roscher <herwig.roscher@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: HV Oscilloscope probe (fwd)


Hi Jim,

> Probably because it forms a capacitive divider.. the 4pF starts to be 
> pretty low impedance (132 ohms at 300 MHz), and working into the 
> usual 1Meg paralleled with 15-20 pF, it's only a 10:1 divider.
> See, e.g., http://www.highvoltageprobes.com/faq.html for a discussion 
> of HV scope probes.
- Thank you for your explanation. So the kind of the divider 
schematic probably causes the voltage across the components to rise 
with frequency and is the reason for the specified decline of applied 
voltage with increasing frequency.


Bye		Herwig

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