the circuit of active probe using FET trace CRO

Question

pls suggest the circuit of active probe using FET trace CRO.

If you can't be bothered to Google "active scope probe", I'm not sure there's much hope for you. — WhatRoughBeast, Jul 18 '14 at 12:49

score 2 · Answer 1 · edited Jul 18 '14 at 12:56

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This is from Troubleshooting Analog Circuits by Bob Pease. He claims 90MHz and Cin < 1pF:

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edited Jul 18 '14 at 12:56

PeterJ

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answered Jul 18 '14 at 12:48

George Herold

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I've just uploaded that to imgur because Stack Exchange have an arrangement where they are kept long term, whereas Dropbox links sometimes disappear. Although it might be worth adding some extra description as text so it's more searchable. – PeterJ Jul 18 '14 at 12:57
Hi @PeterJ, I'm new here. Do I have to add the text? Or can you? JFET active 'scope probe.. or something like that. (I just happened to have the pic in my dropbox, and I thought I'd share – George Herold Jul 18 '14 at 13:11
Hi @George, you can press the edit button to make any additions. I was just thinking maybe just type up a bit of a summary of how it works from the book, probably best to just summarise in your own words a bit rather than copy too much verbatim. – PeterJ Jul 18 '14 at 13:13

score 0 · Answer 2 · edited Apr 13 '17 at 12:33

An immensely valuable resource is available via Google images.
Everyone know that you can search for things on Google.
Fewer people realise what you get when you repeat the same search using Google images.

The "a picture is worth 1000 words" adage tends to apply. Now, instead of reading text and trying to determine relevance, you can look at many pictures very rapidly and click on those which appear relevant visually.
Every picture is linked to a web page and, even if many do not cover what they may at first appear to, this still (usually) produces many good results immensely rapidly via the pictures.

Copying your exact question text into Google images, I used