Everything you ever wanted to know about how Multimeter input protection works.
Using the Fluke 27 as a baseline example.
Service Manual: http://www.testmart.com/webdata/mfr_pdfs/FLU/27______smeng0100.pdf
Forum Topic: http://www.eevblog.com/forum/blog-specific/eevblog-373-multimeter-input-protection-tutorial

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