Jean-Pierre Desrochers
Forum Participant

Thanks Bruce for your nice comments..
— How linear did the meter readings turn out?
Well I had to do some tests to find the ‘appropriate’ components for each meter..
the 0-1mA meter (0-130vac modified) was friendly to accomodate because of the large voltage
I had to reduce to this current range.The voltage drop in the 1N4007 (D2) would not interfere
in the linearity at all. I would say linearity wise I ended up in the 2-3% precision !!
The 0-100mA meter (0-4amp modified) was more touchy..The low current transformer output
needed not to be modified by any non-linear component (like the 1N60 germanium diode D1)
including the current transformer voltage output non-linearity region (when used with current too high).
There has been a ‘sweet spot’ just before the transformer curve started to be non-linear.
I used that max current at 4amp RMS. Again very good linearity around 2-3%.

— What schematic design program do you use – the result looks very neat.
I always used OrCAD Capture and Layout CADs since the 90’s.
Capture produces very ‘elegant’ schematics compared to many others CADs (like Eagle not to name it..)

— No ground connection on the output receptacles – any reason for that ? For safety, I would have had the ground wired.
Well I’m still wondering if I would need one.. The radios that will be on test will be with live chassis
and these chassis will be isolated by this supply and grounded from my tests Equipment probes & leads so.. Hmmm. Don’t know..

— I’ll take a look at frontdesigner3.0 for a project I have in mind – thanks for the reference.
This is a MUST HAVE for front panel designs.
If you have time to take a look at some of my modular synthesizer modules projects
you will find MANY front panel layouts made out of FrontDesigner3.0 .
Just to get its meter graticule maker tool this software Worth it !!
The modular modules build details are here:
By the way, I will have a 4.0A fuse added in series with the variac’s cursor
as many readers recommended it for safety of the auto-transformer
specialy at low secondary voltage with too HIGH current..

Thank you for your time.
Jean-Pierre Desrochers