Has anyone experience with a simple adapter for linearizing a meter which has a non-linear movement?
Thinking about the diode+resistor networks sometimes used between stages for log amps, expanders, compressors, etc.
I have two nice old RF ammeters, thermocouple types, but no thermocouples for them. I'd like to clean 'em up and run them off small toroidal current transformers and rectifier followed by possibly a 'bunch of diodes and resistors' to linearize the curve, but will use an op amp or something active if there's no other way.
I have been thinking that since they are 3mA DC full scale deflection, they could be run as DC voltmeters and conected to some sort of network. Just can't seem to beat my brain hard enough to envision it.
The full scale reading of 20A occurs at 3mA DC. The scales are
almost linear as well, so that would be good enough. They are for relative indication only. They match a set of other meters for another part of the same old frankenrat I been working off and on for a few years.. Would be super-nice in the antenna matcher section.
Thanks!
p.s. the blue and orange are the responses of the meters for the positions on the scale. The green is what i want to approach.
