VTVMs with active RF probes

Over on the Antique Radio Forum, there's a conversation about VTVMs with a vacuum tube diode in the RF probe. Here's one of my favorites: the Sylvania Polymeter 302.

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Sylvania Polymeter 302

There are a few more VTVM's with active RF probes in my collection.

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General Radio 1806-A

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Precision EV-20

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Hewlett Packard HP 410B

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Hewlett Packard HP 410C

(to do: complete this table)

Input capacitance

Meter RF probe input capacitance
Sylvania Polymeter 302 3.3 pF

© Steve Byan 2011-2019