What is a sold state vacuum tube voltmeter?

Probably a VTVM with solid state replacements for the tubes.

It's an electronic voltmeter that uses FETs instead of vacuum tubes.

On Tue, 19 May 2009 16:16:59 -0400, mm put finger to keyboard and composed:

I found a "Department of the Army" technical manual: ftp://bama.sbc.edu/downloads/hp/410c/410c.pdf

I found the following statement:

==========================================================

2-4. The Model 410C is transistorized except for one vacuum tube and requires no special cooling. ==========================================================

See page 57 for a circuit diagram.

I found this amusing:

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1-A.4. Reporting Errors and Recoin. mending Improvements

You can help improve this manual. If you find any mistakes or if you know of a way to improve the procedures, please let us know. ==========================================================

- Franc Zabkar

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Please remove one \'i\' from my address when replying by email.

An amplified solid state voltmeter made to emulate the impedance of a Vacuum Tube Voltmeter, so that it will accurately read voltages specified in service data as read by a VTVM. Input impedance is usually specified as 11 Megohms for all DC Volt ranges and 10 Megohm for AC Volt ranges rather than the Ohm/Volt specification for multimeters and VOMs.

The higher input impedance causes minimal loading of the circuit under test, so less disruption of the circuit and more accurate readings.

The unit in the picture is a well known quality instrument widely specified in lab manuals but looks like the probe wires need replacing.

Thats a voltmeter that has been sold....

Thanks to all of you. Especiialy JB.

Yes, it's been solidly sold. :)

It's a transistorized VTM that should only be used to test vacuum tubes.

Hmmm... Does that mean that VTVMs should only be used to test transistors?

OK, here's a complete non-sequitur triggered by my brain's tendency to free associate ...

Seymour Cray was once asked what kind of computer he used to design the original Cray supercomputer. His reply: "I used a #2 pencil and a quadrille pad."

Some years go by, and he's being interviewed again. The interviewer says, "Did you know that Apple bought a Cray supercomputer to help them design their new Mac?"

"That's funny," Mr. Cray says, "I just bought a Mac to help me design my new supercomputer."

That's one of my favorite stories.

I think you're on to something Bill.

LOLZ!

Good story. My first computer design (CPU board for a series of devices), was done with a pencil & a 5mm square graph pad.

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