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I like the AD623A differential amplifier?because it takes differential inputs and I can set the output to be 2.5v for 0v in.?

Now?+5v out represents max positive input (say?+10V), 2.5v out represents 0v input, and 0v out represents max negative input (-100V). This scales the input to fit the 5 volt range of the ADC on a PIC. Adjust according to the ADC you are using. The schematic shows an application looking at a shunt in a 12v battery path and the output goes to a PIC ADC to read positive or negative current. R is the shunt. S2 is used to short the input to zero the amplifier with R7, it must be DPDT or you might be fighting the shunt for 10 amps. The 5v supply needs to be stable,?use?a precision?regulator with 5.000v out..

Peter??

On Mon, Nov 8, 2021 at 12:50 PM peter bunge via <bunge.pjp=[email protected]> wrote:

Look at the schematics, the step amplifier for example. It shows 2v/div for the steps. Connect an instrument amplifier to the Steps Out and adjust the gain.

The deflection amplifiers are trickier but can be done with an instrumentation amplifier with proper scaling and offsets. You will need to protect the circuit from the 100 volt signals.

Good luck with the readout lamps for the ranges, but it is possible.?

Peter

On Mon, Nov 8, 2021 at 11:48 AM green <hrgerson@...> wrote:

hi,

Just to pull the conversation back to the?? *electronics*? of the replacement of a XYZ CRT with an LCD ??
???? { rather than the programming or software, for now }.

Does anyone have any technical expertise with? "picking off" ? the vector type (non-raster) CRT XYZ signals? (presumably from the low voltage deflection amplifiers)? ?

Assuming that somewhere in the deflection amplifier signal chain, there might be some low voltage +/- 5V signals that could be used
? --- so that could then be fed into an LCD module ( such as the $55? STM32F746G-DISCO module ?).

For this project question, the CRT display is a simple XYZ vector display, not a raster CRT:

The NewScope modules are too expensive to consider,
and this CRT issue is not concerned with longevity nor with hypothetical future replacements of the LCD with another LCD, etc.
Nor with the use of yet another CRT.

The point being that the STM LCD module may represent the possibility of actually capturing the data from, say a Tek 576 Curve Tracer( as an example), that would allow such data to be imported into a laptop for data manipulation, comparison? and file storage that could be useful for component R&D & project development, beyond the current instrument limitations.

The CRT's of these type of instruments are dying and are not easily replaceable.
Why not move forward with an inexpensive LCD module for these instruments ?

>>>? In any event, if anyone has direct technical experience with the type of XYZ CRT deflection signal pick-off and manipulation posed by this question, their experience or thoughts would be appreciated !
(i.e. , specifically for the Tek 576 CT,? would those signals have to be buffered or level shifted, etc. ?)

-- If anyone has come across a Website or a Blog conveying? *inexpensive*? vector XYZ CRT replacement ( or signal capture ) with an LCD,
I'd appreciate knowing about it !!
Not sure if there are other descriptions or jargon ( i.e.? " Scan Converter " etc. ) that might have been used to describe this sort of problem, perhaps published in "The Review of Scientific Instruments", or IEEE Transactions ?

There must have been sectors of the industry that encountered and solved this issue *inexpensively* ?
?
thank you,
rick?

Note:
-- A number of Web references for vector XYZ type concepts have been discussed, including a well explained reference to a Patent, in the Tek Groups .io discussion:?
/g/TekScopes/topic/86718765
-- Not worried about the Tek 576 switch settings / plastic fiber display issues for now;? - those are simply a decode issue which can be easily solved and added to the converted LCD display, later on !?