On 9/6/2013 9:00 AM, n8zu wrote:
Before I forget I'm using opto couplers for plate voltage and current to the VTVM 'cause I use a plus minus supply that needs a floating ground. So plus minus 1500vdc for the plate supply on a floating ground for the plate circuit, and 500vdc plus minus at an earth/input/output ground for the screen and control grid, with the screen at earth/input/output ground so I can run control grid swapped to input ground for drive from the transmitter.

I haven't noticed anyone asking you why you want to build a VTVM for
this purpose. Why not use a circuit designed in the last 50 years? Is
there some inherent advantage to a VTVM in this application that a
transistorized circuit would not be able to improve on? Or is this a
nostalgia effort?

--

Rick