High voltage capacitor discharger circuit arduino

Thread Starter


Joined Jul 23, 2008
Hello, i got my Atlas ESR Plus (ESR70) - Capacitor Analyser. It has a integrated voltage discharger but that's for low voltages.
It's always safe to discharge caps before you use any measuring, or touch them !

So I decided to make one using arduino nano, some lcd with bargraph etc. Simple wire with 470ohm resistor does not cut it.
If you wonder why 470ohm, then see this video:

To save space I should use the D2PAK resitors? as I want as small form factor as possible as I try to squeeze this into something like typical SMD tweezers. http://www.burntec.com/image/cache/...rt_smd_tester_tweezer_style_meter-500x500.jpg

Obviously this should work any way you connect it without checking polarity! So simple voltage divider calculated to make 5V at 1000V input will not work I think.
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Hypatia's Protege

Joined Mar 1, 2015
Inasmuch as your post appears to be soliciting feedback, I offer the following;

1) Safety requires that divider component characteristics (Spec; resistance, power handling capability and maximum EMF drop) are consistent with the proposed instrument's anticipated dynamic range -- Please be advised that 'one size fits all' represents a dubious -quite often dangerous- approach - at best!

2) Inasmuch as you will be incorporating a microcontroller, you may wish to implement additional features (e.g. dielectric analysis, 'electrolytic reformation', etc...) -- IMNSHO Automation merely of a safety discharge feature represents 'overkill' and, most 'tragically', lost opportunity!:cool:

3) Beware of dielectric absorption!

Best regards and good luck!