This is a follow-up on this question:

How to Design Arduino Voltage and Current Sensing Shield

Thanks to user bigjosh, I read the article:


and I started designing my own board for sensing current/voltage.

Now the question I have is the following. In the above-mentioned article they use simple power-transformer for decreasing the grid voltage to a reasonable value. Can I use a current-sense transformer such as the one in


instead of a power-transformer.

In my opinion, it would be even better as due to the small number of primary coils the distortion in the EMF would be smaller and the distortion in the resulting signal would be smaller.

  • \$\begingroup\$ Please state exactly what you want to connect the CT to and what voltage and current you expect to derive from it. The energy monitor link in your question may not be available next year invalidating this question. Better to put key information into the question rather than rely on a link. \$\endgroup\$
    – Andy aka
    Commented May 7, 2015 at 7:40

1 Answer 1


No, you can not use current transformer to sense voltage. You need a voltage sense transformer, and trying to use current-sense transformer instead will be very bad. Your particular one can have inductance of up to just 8000 microhenries (as opposed to multiple henries power transformers), which means it will dissipate ~150000 watts (and instantly explode) when if you connect it across the mains.

If you are asking these kinds of questions, I highly recommend sticking up to pre-made power adapters and clamp-on current transformers (http://www.digikey.com/product-detail/en/CR3110-3000/582-1004-ND/1045160) which do not require you to mess with exposed high-voltage wiring at all.

  • \$\begingroup\$ Why would 8000 uH result in a dissipation of ~150kW when connected across the mains, is there an equation that helps determine this? \$\endgroup\$
    – plu
    Commented Jan 23, 2020 at 19:10

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