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Old 21st Sep 2018, 8:26 pm   #8
TrevorG3VLF
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Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
Posts: 1,378
Default Re: Electrolytic capacitor reformer meter circuits

To keep reasonably close to the specified capacitor values in the voltage doubler circuit, I used two 33uF 400V electrolytics in series to achieve the quoted 16uF values. I should have included voltage sharing resistors across each cap to avoid the possibility of exceeding the working voltage of the cap. In practice, the Panasonic caps were well matched so there have been no problems. It's not difficult to calculate the required sharing resistor values, typically 10M Ohm will be suitable in this case.


You do not need voltage sharing resistors, the circuit is a pair of half wave circuits in series, there is no way the normal voltage can be exeeded.

Why is a smoothed supply required in a reformer? The capacitors are needed for the doubler of course.
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